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Tamilnadu Samacheer Kalvi 10th Science Solutions Chapter 10 Types of Chemical Reactions

Samacheer Kalvi 10th Science Types of Chemical Reactions Text Book Back Questions and Answers

I. Choose the correct answer:

Question 1
H_2(g) + Cl_29(g) → 2HCl_(g)
(a) Decomposition Reaction
(b) Combination Reaction
(c) Single Displacement Reaction
(d) Double Displacement Reaction
Answer:
(a) Decomposition Reaction

Question 2.
Photolysis is a decomposition reaction caused by ______.
(a) heat
(b) electricity
(c) light
(d) mechanical energy
Answer:.
(c) light
Hint:
\(2 \mathrm{AgBr}_{(\mathrm{s})} \stackrel{\mathrm{Light}}{\longrightarrow} 2 \mathrm{Ag}_{(\mathrm{s})}+\mathrm{Br}_{2(\mathrm{g})}\)

Question 3.
A reaction between carbon and oxygen is represented by C_(s) + O_2(g) → CO_2(g) + Heat. In which of the type(s), the above reaction can be classified?
(i) Combination Reaction
(ii) Combustion Reaction
(iii) Decomposition Reaction
(iv) Irreversible Reaction
(a) (i) and (ii)
(b) (i) and (iv)
(c) (i), (ii) and (iii)
(d) (i), (ii) and (iv)
Answer:
(d) (i), (ii) and (iv)

Question 4.
The chemical equation \(\mathrm{Na}_{2} \mathrm{SO}_{4(\mathrm{aq})}+\mathrm{BaCl}_{2(\mathrm{aq})} \rightarrow \mathrm{BaSO}_{4(\mathrm{s})} \downarrow+2 \mathrm{NaCl}_{(\mathrm{aq})}\) represents which of the following types of reaction?
(a) Neutralisation
(b) Combustion
(c) Precipitation
(d) Single displacement.
Answer:
(c) Precipitation
Hint: This reaction involves the precipitation of white BaSO₄ by mixing of Na₂SO₄ (aq) and BaCl₂ (aq). Hence it belongs to precipitation reaction.

Question 5.
Which of the following statements are correct about a chemical equilibrium?
(i) It is dynamic in nature
(ii) The rate of the forward and backward reactions are equal at equilibrium
(iii) Irreversible reactions do not attain chemical equilibrium
(iv) The concentration of reactants and products may be different
(a) (i), (ii) and (iii)
(b) (i), (ii) and (iv)
(c) (ii), (iii) and (iv)
(d) (i), (iii) and (iv)
Answer:
(a) (i), (ii) and (iii)

Question 6.
A single displacement reaction is represented by \(\mathrm{X}_{(\mathrm{s})}+2 \mathrm{HCl}_{(\mathrm{aq})} \rightarrow \mathrm{XCl}_{2(\mathrm{aq})}+\mathrm{H}_{2(\mathrm{g})}\). the following(s) could be X?
(i) Zn
(ii) Ag
(iii) Cu
(iv) Mg.
Choose the best pair.
(a) i and ii
(b) ii and iii
(c) iii and iv
(d) i and iv.
Answer:
(d) i and iv.
Hint:
Zn + 2HCl → ZnCl₂ + H₂
Mg + 2HCl → MgCl₂ + H_2.

Question 7.
Which of the following is not an “element + element → compound” type reaction?
(a) C_(s) + O_2(g) → CO_2(g)
(b) 2K_(s) + Br_2(l) → 2KBr_(s)
(c) 2CO_(g) + O_2(g) → 2CO_2(g)
(d) 4Fe_(s) + 3O_2(g) → 2Fe₂O_3(s)
Answer:
(c) 2CO_(g) + O_2(g) → 2CO_2(g)

Question 8.
Which of the following represents a precipitation reaction?
(a) A_(s) + B_(s) → C_(s) + D_(s)
(b) A_(s) + B_(aq) → C_(aq) + D_(l)
(c) A_(aq) + B_(aq) → C_(s) + D_(aq)
(d) A_(aq) + B_(s) → C_(aq) + D_(l)
Answer:
(c) A_(aq) + B_(aq) → C_(s) + D_(aq)

Question 9.
The pH of a solution is 3. Its [OH^–] concentration is ______.
(a) 1 × 10^-3 M
(b) 3 M
(c) 1 × 10^-11 M
(d) 11 M.
Answer:
(c) 1 × 10^-11 M
Hint: pH = 3
It means [H⁺] = 10^-3
[H⁺] [OH^–] = 10^-14
[10^-3] [OH^–] = 10^-14
[OH^–] = 10^-11

Question 10.
Powdered CaCO₃ reacts more rapidly than flaky CaCO₃ because of :
(a) large surface area
(b) high pressure
(c) high concentration
(d) high temperature
Answer:
(a) large surface area

II. Fill in the blanks:

1. A reaction between an acid and a base is called ………..
2. When zinc metal is placed in hydrochloric acid, ………. gas is evolved.
3. The equilibrium attained during the meiting of ice is known as ………..
4. The pH of a fruit juice is 5.6. If you add slaked lime to this juice, its pH ……….
5. The value of ionic product of water at 25 °C is ………..
6. The normal pH of human blood is …………
7. Electrolysis is type of ……….. reaction.
8. The number of products formed in a synthesis reaction is ………..
9. Chemical volcano is an example for ……….. type of reaction.
10. The ion formed by dissolution of H⁺ in water is called …………
Answer:
1. neutralization
2. H₂
3. physical equilibrium
4. increases to ‘7’
5. 1 × 10^-14 mol² dm^-6
6. 7.4
7. decomposition
8. 1
9. decomposition
10. hydronium ion

III. Match the following:

Question 1.
Identify the types of reaction:

Answer:
A. (iii)
B. (i)
C. (iv)
D. (ii)

IV. True or False: (If false give the correct statement)

1. Silver metal can replace hydrogen gas from nitric acid.
2. The pH of rain water containing dissolved gases like SO₃, CO₂, NO₂ will be less than 7.
3. At the equilibrium of a reversible reaction, the concentration of the reactants and the products will be equal.
4. Periodical removal of one of the products of a reversible reaction increases the yield.
5. On dipping a pH paper in a solution, it turns into yellow. Then the solution is basic.

Answer:

1. False – Silver cannot displace H₂ from HNO₃ acid, since it is placed below hydrogen in the activity series.
2. True
3. False – At equilibrium the concentration of the reactants and products do not change it remains constant, but the concentration of the reactants and the products will not be equal.
4. True
5. False – The solution is neutral if the solution is basic it will be green in colour.

V. Short answer questions:

Question 1.
When an aqueous solution of potassium chloride is added to an aqueous solution of silver nitrate, a white precipitate is formed. Give the chemical equation of this reaction.
Answer:

Question 2.
Why does the reaction rate of a reaction increase in raising the temperature?
Answer:
On increasing temperature heat is supplied to the reactant. This energy breaks more bonds and thus speed up the chemical reaction. Foods kept at room temperature spoils faster than that kept in the refrigerator.

Question 3.
Define combination reaction. Give one example for an exothermic combination reaction.
Answer:
A combination reaction is a reaction in which two or more reactants combine to form a compound.
Eg: C_(s) + O_2(g) → CO_2(g) + heat

Question 4.
Differentiate reversible and irreversible reactions.
Answer:

VI. Answer in detail:

Question 1.
What are called thermolysis reactions?
Answer:
Thermal decomposition reactions are called ‘thermolysis’ reaction. In this type of reaction, the reactant is decomposed by applying heat. There are two types of thermolysis reactions. They are:
(i) Compound to element / element decomposition:
A compound is decomposed into two elements.
Eg:

(ii) Compound to compound / compound decomposition:
A compound is decomposed into two compounds.
Eg:

Question 2.
Explain the types of double displacement reactions with examples.
Answer:
There are two major classes of double displacement reactions. They are,
(i) Precipitation Reactions: When aqueous solutions of two compounds are mixed, if they react to form an insoluble compound and a soluble compound, then it is called precipitation reaction.
\(\mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2(\mathrm{aq})}+2 \mathrm{KI}_{(\mathrm{aq})} \rightarrow \mathrm{PbI}_{2(\mathrm{s})} \downarrow+2 \mathrm{KNO}_{3(\mathrm{aq})}\)

(ii) Neutralisation Reactions: Another type of displacement reaction in which the acid reacts with the base to form a salt and water. It is called ‘neutralisation reaction’ as both acid and base neutralize each other.
\(\mathrm{NaOH}_{(\mathrm{aq})}+\mathrm{HCl}_{(\mathrm{aq})} \rightarrow \mathrm{NaCl}_{(\mathrm{aq})}+\mathrm{H}_{2} \mathrm{O}_{(\mathrm{l})}\).

Question 3.
Explain the factors influencing the rate of a reaction.
Answer:
Important factors that affect rate of a reaction are:

1. Nature of the reactants
2. Concentration of the reactants
3. Temperature
4. Catalyst
5. Pressure
6. Surface area of the reactants

1. Nature of the reactants : The reaction of sodium with hydrochloric acid is faster than that with acetic acid, because Hydrochloric acid is a stronger acid than acetic acid and thus more reactive. So, the nature of the reactants influence the reaction rate.
2Na_(s) + 2HCl_(aq) → 2NaCl_(aq) + H_2(g) (fast)
2Na_(s) + 2CH₃COOH_(aq) → 2CH₃COONa_(aq) + H_2(g) (slow)

2. Concentration of the reactants : Changing the amount of the reactants also increases the reaction rate. More the concentration, more particles per volume exist in it and hence faster the reaction. Granulated zinc reacts faster with 2M hydrochloric acid than 1M hydrochloric acid.

3. Temperature : Most of the reactions go faster at higher temperature. Because adding heat to the reactants provides energy to break more bonds and thus speed up the reaction. Calcium carbonate reacts slowly with hydrochloric acid at room temperature. When the reaction mixture is heated the reaction rate increases.

4. Pressure : If the reactants are gases, increasing their pressure increases the reaction rate. This is because, on increasing the pressure the reacting particles come closer and collide frequently.

5. Catalyst : A catalyst is a substance which increases the reaction rate without being consumed in the reaction. In certain reactions, adding a substance as catalyst speeds up the reaction. For example, on heating potassium chlorate, it decomposes into potassium chloride and oxygen gas, but at a slower rate. If manganese dioxide is added, it increases the reaction rate.

6. Surface area of the reactants : Powdered calcium carbonate reacts more readily with hydrochloric acid than marble chips. Because, powdering of the reactants increases the surface area and more energy is available on collision of the reactant particles. Thus, the reaction rate is increased.

Question 4.
How does pH play an important role in everyday life?
Answer:

• The pH of blood is almost 7.4. Any increase or decrease in this value leads to diseases
• Citrus fruits require slightly alkaline soil, while rice requires acidic soil and sugarcane requires neutral soil.
• If the pH of rainwater becomes less than 7, it becomes acid rain which is harmful in day-to-day life.
• pH changes cause tooth decay.
• During indigestion, the stomach produces too much acid and this causes pain and irritation.

Question 5.
What is chemical equilibrium? What are its characteristics?
Answer:
Chemical equilibrium is a state of a reversible chemical reaction where the,
Rate of forward reaction = Rate of backward reaction.
No change in the amount of the reactants and products takes place.
Characteristics of equilibrium:

1. In a chemical equilibrium, the rates of the forward and backward reactions are equal.
2. The observable properties such as pressure, concentration, colour, density, viscosity etc., of the system remain unchanged with time.
3. The chemical equilibrium is a dynamic equilibrium, because both the forward and backward reactions continue to occur even though it appears static externally.
4. In physical equilibrium, the volume of all the phases remain constant.

VII. HOT Questions:

Question 1.
A solid compound ‘A’ decomposes on heating into ‘B’ and a gas ‘C’ On passing the gas ‘C’ through water, it becomes acidic. Identify A, B and C.
Answer:
A – CaCO₃, solid compound
‘A’ decomposes on heating into ‘B’ and a gas ‘C’.

On passing the gas CO₂ through water, it becomes acidic.

A – CaCO₃, Calcium carbonate
B – CaO, Calcium oxide
C – CO₂, Carbondioxide gas

Question 2.
Can a nickel spatula be used to stir copper sulphate solution? Justify your answer.
Answer:
No, nickel spatula cannot be used to stir the copper sulphate solution. Actually, on the basis of activity series, nickel is more reactive than copper, so nickel will displace copper from its solution and copper will be deposited on nickel spatula.

VIII. Solve the following problems:

Question 1.
Lemon juice has a pH 2, what is the concentration of H⁺ ions?
Answer:
pH = – log [H⁺]
[H⁺] = antilog of [-pH]
= antilog [-2]
[H⁺] = 10^-2 M
[OR]
PH = – log [H⁺]
[H⁺] = 10^-pH
[H⁺] = 10^-2M

Question 2.
Calculate the pH of 1.0 × 10^-4 molar solution of HNO₃.
Answer:
pH = – log [H⁺]
HNO3 → H⁺ + NO₃^–
pH = -log [1 × 10^-4]
= -(-4)log₁₀ 10 = 4
pH = 4

Question 3.
What is the pH of 1.0 x 10^-5 molar solution of KOH?
Answer:
KOH → K⁺ + OH^–
pOH = -log[OH^–]
= -log [1 × 10^-5]
pOH = 5
pH + pOH = 14
∴ pH of KOH = 14 – 5 = 9
pH = 9

Question 4.
Laundry detergent has a pH 8.5, What is the concentration of H⁺ ions?
Answer:
pH = 8.5
pH = – log [H⁺]
[H⁺] = 10^-pH
[H⁺] = 10^-8.5
[H⁺] = 3.16 × 10^-9 M

Question 5.
The hydroxide ion concentration of a solution is 1 × 10^-11M. What is the pH of the solution?
Answer:
[OH^–] = 1 × 10^-11 M
pOH = – log[OH^–]
= – log[1 × 10^-11]
= -log₁₀1 – log₁₀10^-11
= -(-11) log₁₀10 = 11
pOH = 11
pH + pOH = 14
pH = 14 – 11
pH = 3

Samacheer Kalvi 10th Science Types of Chemical Reactions Additional Important Questions and Answers

I. Choose the correct answer:

Question 1.
The unit of rate of a reaction is:
(a) dm³/mol
(b) dm^-3
(c) mol dm^-3
(d) mol
Answer:
(c) mol dm^-3

Question 2.
As the molecule is dissociated by the absorption of heat it is otherwise called as ______.
(a) Thermolysis
(b) Photolysis
(c) Electrolysis
(d) None of these.
Answer:
(a) Thermolysis

Question 3.
The chemical formula of marble is:
(a) CaCO₃
(b) MgCO₃
(c) Na₂CO₃
(d) PbCO₃
Answer:
(a) CaCO₃

Question 4.
As the decomposition is caused by light, this kind of reaction is called ______.
(a) Thermolysis
(b) Photolysis
(c) Electrolysis
(d) None of these.
Answer:
(b) Photolysis

Question 5.
Fluorine will displace the following halide ion from the solution:
(a) chloride
(b) bromide
(c) iodide
(d) all the above
Answer:
(d) all the above

Question 6.
The decomposition of AgBr into grey coloured silver metal is an example of ……… reaction.
(a) compound to element/element
(b) compound to compound/compound
(c) combination
(d) neutralization
Answer:
(a) compound to element/element

Question 7.
The Metathesis reaction among the following is:
(a) C₃H_8(g) +5O_2(g) → 3CO_2(g) + 4H₂O + heat
(b) Zn_(s) + CuSO_4(aq) → ZnSO_4(aq) + Cu_(s)
(c) HNO_3(aq) + NH₄OH_(aq) → NH₄NO_3(aq) + H₂O_(l)

Answer:
(c) HNO_3(aq) + NH₄OH_(aq) → NH₄NO_3(aq) + H₂O_(l)

Question 8.
KI and Pb(NO₃)₂ solutions are mixed to give a precipitate. What is the colour of the precipitate?
(a) White
(b) Brown
(c) Red
(d) Yellow.
Answer:
(d) Yellow

Question 9.
The pH of rain water is approximately:
(a) 7
(b) 8
(c) 4
(d) 14
Answer:
(a) 7

Question 10.
Most of the reactions go faster at ______.
(a) low temperature
(b) moderate temperature
(c) 0°C
(d) high temperature.
Answer:
(d) high temperature

II. Fill in the blanks.

1. A chemical equation provides information on the ……….. of the substances and the reaction condition.
2. The symbol ‘aq’ in a chemical equation represent the physical state of the substance as ……….
3. 2Na_(s) + Cl_2(g) → 2NaCl_(s) represent the combination reaction between a ……… and ……
4. After white washing with a solution of slaked lime a thin layer of ……….. is formed.
5. Reactions in which heat is absorbed is called ……….. reactions.
6. Electrolytic refining of copper is based on ……….. reaction.
7. When 10^-6 mole of a monobasic strong acid is dissolved in water, the pH of the solution is ………..
8. When pH of a solution is 2, the [H⁺] in mol/L is ……….
9. Combustion of coal is an example of ………. reaction.
10. [ ] represents the concentration of either the reactant or product in ……….
Answer:
1. physical state
2. aqueous solution
3. metal, non-metal
4. CaCO₃
5. endothermic
6. electrolytic decomposition
7. 6
8. 1 × 10^-2
9. irreversible
10. mol/Lit

III. Match the following.

Question 1.
Match the following table:

Answer:
A. (v)
B. (iii)
C. (iv)
D. (ii)
E. (i)

Question 2.
Match the following table:

Answer:
A. (v)
B. (iv)
C. (i)
D. (iii)
E. (ii)

Question 3.
Match the following table:

Answer:
A. (iii)
B. (v)
C. (iv)
D. (ii)
E. (i)

Question 4.
Match the following table:

Answer:
A. (iv)
B. (v)
C. (i)
D. (ii)
E. (iii)

IV. True or False: (if false give the correct statement)

1. Formation of calcium silicate from silica and calcium oxide is a combination reaction.
2. Most of the combination reactions are endothermic in nature.
3. Decomposition of mercuric oxide into mercury and O₂ is an example of . photolysis.
4. Chlorine can displace fluoride ion from its aqueous solution.
5. Magnesium is more reactive than iron.

Answer:

1. True
2. False – Most of the combination reactions are exothermic in nature.
3. False – Decomposition of mercuric oxide into mercury and O₂ is an example of thermolysis.
4. False – Chlorine is less reactive than Fluorine, so it cannot displace fluoride ion from its aqueous solution.
5. True

V. Short answer questions:

Question 1.
Write a note on double displacement reaction with an example.
Answer:
When two compounds react, if their ions are interchanged, then the reaction is called double displacement reaction.
Eg: NaOH_(aq) + HCl_(aq) → NaCl_(aq) + H₂O

Question 2.
Identify the wrong statements and correct them.

1. Sodium benzoate is used in food preservative.
2. Nitric acid is not used as fertilizer in agriculture.
3. Sulphuric acid is called the king of chemicals.
4. The pH of acid is greater than 7.
5. Acetic acid is used in aerated drinks.

Answer:

1. Correct statement.
2. Wrong statement. Nitric acid is used as a fertilizer in agriculture.
3. Correct statement.
4. Wrong statement. The pH of the acid is lesser than 7.
5. Wrong statement. Carbonic acid is used in aerated drinks.

Question 3.
Why a combustion reaction may be called as an exothermic oxidation?
Answer:
In a combustion reaction heat is evolved, it is an exothermic reaction. As oxygen is added, it is also an oxidation. So, combustion may be called as an exothermic oxidation.

Question 4.
Take two conical flasks. Label them as I and II. Take a small amount of copper sulphate solution in the first conical flask. Take a small amount of granulated zinc in the second conical flask. Allow the copper sulphate solution to react with the zinc.

1. Name the type of reaction.
2. Say whether the metal zinc is more reactive or less reactive.
3. Write a complete and balanced reaction.
4. Say whether this change is reversible or irreversible.

Answer:

1. The reaction taken place is displacement reaction.
2. Metal zinc is more reactive.
3. Balanced chemical equation.
   \(\mathrm{Zn}_{(\mathrm{s})}+\mathrm{CuSO}_{4(\mathrm{aq})} \rightarrow \mathrm{ZnSO}_{4(\mathrm{aq})}+\mathrm{Cu}_{(\mathrm{s})} \downarrow\)
4. This change is an irreversible change.

Question 5.
What is an irreversible reaction? Give an example.
Answer:
The reaction that cannot be reversed is called irreversible reaction. The irreversible reactions are unidirectional, i.e., they take place only in the forward direction. Consider the combustion of coal into carbon dioxide and water.

Question 6.
Define the rate of a reaction.
Answer:
“Rate of a reaction is the change in the amount or concentration of any one of the reactants or products per unit time”.
Consider the following reaction,
A → B
The rate of this reaction is given by
Rate = –\(\frac{d[A]}{dt}\) = +\(\frac{d[B]}{dt}\)
Where,
[A] – Concentration of A
[B] – Concentration of B
The negative sign indicates the decrease in the concentration of A with time. The positive sign indicates the increase in the concentration of B with time.

Question 7.
What is meant by combination reaction? Give an example.
Answer:
A reaction in which a single product is formed from two or more reactants is known combination reaction.
2Mg + O₂ → 2MgO.

Question 8.
What is a catalyst?
Answer:
A catalyst is a substance which increases the reaction rate without being consumed in the reaction.

Question 9.
Define Displacement reaction. Give an example.
Answer:
The reaction in which a more reactive element displaces a less reactive element from its compound is called displacement reaction.
\(\mathrm{Pb}+\mathrm{CuCl}_{2} \longrightarrow \mathrm{PbCl}_{2}+\mathrm{Cu} \downarrow\)
Lead displaces copper from copper chloride solution.

Question 10.
When a aerated soft drink bottle is kept open it will go flat. Why?
Answer:
(i) In the sealed aerated soft drink bottle, the dissolved CO₂, in the form of carbonic acid and gaseous CO₂ are in equilibrium.
(ii) When we open the bottle the gaseous CO₂ will escape and the dissolved CO₂ begins to undissolve to the gas phase to maintain the equilibrium. So when we keep the bottle open for a long time it will go flat with all the dissolved CO₂ gone.

Question 11.
Can copper displace zinc or lead from their salt solutions?
Answer:
No, copper cannot displace zinc or lead from their salt solutions. Because copper is less reactive than zinc and lead.

Question 12.
What is called as acid rain?
Answer:
The pH of rain water is approximately ‘7’ but when the air is polluted with oxides of S and N, they get dissolved in the rain water and make its pH less than 7, then it is called acid rain.

Question 13.
Write the differences between combination and decomposition reaction.
Answer:

VI. Answer in detail:

Question 1.
Two acids ‘A’ and ‘B’ were kept in beakers. Acid ‘A’ undergoes partial dissociation in water, whereas acid ‘B’ undergoes complete dissociation in water.

1. Of the two acids ‘A’ and ‘B’ which is weak acid and which is strong acid?
2. What is a weak acid?
3. What is a strong acid?
4. Give one example of each.

Answer:

1. Of the two acids ‘A’ and ‘B’, ‘A’ is a weak acid and ‘B’ is a strong acid.
2. A weak acid is the one which ionises partially when dissolved in water.
3. A strong acid is the one which ionises completely when dissolved in water.
4. Weak acid – Acetic acid(CH₃COOH)
   Strong acid – Sulphuric acid (H₂SO₄).

Question 2.
Sodium hydroxide and HCl acid react as shown in this equation
NaOH_(aq)4 + HCl_(aq) → NaCl_(aq) + H₂O
(i) Which type of chemical reaction is this?
Answer:
Neutralization reaction

(ii) The reaction is exothermic. Explain what that means?
Answer:
When heat is evolved during a chemical reaction it is called exothermic.

(iii) Differentiate exothermic and endothermic reaction.
Answer:
Exothermic :

1. Heat is evolved.
2. Temperature increases.

Endothermic :

1. Heat is absorbed.
2. Temperature decreases.

(iv) What happens to the temperature of the solution as the chemicals react?
Answer:
Temperature of the solution increases.

Question 3.
Take two conical flasks. Label them as I and II. Take a small amount of CuSO₄ in the I conical flask and small amount of granulated Zinc in the II conical flask. Allow the CuSO₄ solution to react with Zinc.
(i) Name the type of reaction.
Answer:
Displacement reaction.

(ii) Say whether the metal Zn is more reactive or less reactive.
Answer:
Zinc is more reactive than Copper.

(iii) Write the complete and balanced reaction.
Answer:
Zn_(s)+ CuSO_4(aq) → ZnSO_4(aq) + Cu_(s)↓

(iv) Say whether this change is reversible or irreversible
Answer:
Irreversible.

Question 4.
Suggest a reason for each observation given below.

1. In fireworks, powdered magnesium is used rather than magnesium ribbon.
2. Zinc and dilute H₂SO₄ react much more quickly when a few drops of copper sulphate solutions are added.
3. The reaction between magnesium carbonate and dilute hydrochloric acid speeds up when some concentrated HCl is added.

Answer:

1. In fireworks, powdered magnesium is used because it has more surface area than magnesium ribbon. Because of more surface area, powdered magnesium reacts faster than magnesium ribbon.
2. Zinc and dilute H2SO4 react much more quickly when a few drops of copper sulphate solution is added. Copper sulphate acts as a catalyst which increases the rate of the reaction.
3. When the concentration of the reactants increases, the rate of the reaction also increases. So the reaction between magnesium carbonate and dilute hydrochloric acid speeds up by the addition of some concentrated HCl.

VII. Hot Questions:

Question 1.

Answer:
According to the rate Law for the reaction.
2N₂O₅ → 4NO₂ + O₂

2K₁ = K₂ = 4K₃ [neglecting negative and positive signs]

Question 2.
When solutions of silver nitrate and potassium bromide are mixed, a pale yellow precipitate is formed.
The ionic equation for the reaction is Ag⁺ + Br^– → AgBr

1. (a) What is the name of the pale yellow precipitate?
   (b) Is it soluble or insoluble?
2. Is the formation of silver bromide precipitate, a result of redox reaction or not? Justify your answer.
3. What is this type of reaction called?

Answer:

1. (a) The pale yellow precipitate is silver bromide.
   (b) Silver bromide is sparingly soluble.
2. Yes, the formation of silver bromide precipitate is due to redox reaction. Ag⁺ gains electron (reduction) and Br^– loses electron (oxidation). So it is a redox reaction.
3. This reaction is a double displacement reaction.

VIII. Numericals:

Question 1.
The hydrogen ion concentration of a fruit juice is 3.3 × 10^-2M. What is the pH of the juice? Is it acidic or basic?
Answer:
[H⁺] = 3.3 × 10^-2 M
Formula:
pH = -log[H⁺]
pH = -log[3.3 × 10^-2]
= -[log 3.3 + log 10^-2]
= -[0.5185 – 2 log₁₀10]
= -0.5185 + 2 log₁₀10 [log₁₀10 = 1]
= -0.5185 + 2
pH = 1.4815
Since pH is less than 7, the solution is acidic.

Question 2.
If a solution has a pH of 7.41, determine its H⁺ concentration.
Answer:
pH = 7.41
Formula:
[H⁺] = antilog[-pH]
= antilog[-7.41] = 10^-7.41
= 3.89 × 10^-8M

Question 3.
The pH of a solution is 5.5 at 25°C. Calculate its [OH^–].
Answer:
pH = 5.5
Since pH + pOH = 14
pOH = 14 – pH
= 14 – 5.5 = 8.5
[OH^–] = 10^-pOH
= 10^-8.5
= 3.16 × 10^-9M
(OR)
[OH^–] = antilog[-8.5]
= 3.16 × 10^-9M
[OH^–] = 3.16 × 10^-9M

Question 4.
Calculate the pH of 0.001 M HCl solution.
Answer:
Since HCl is a strong acid, it dissociates
HCl → H⁺ + Cl^–
[H⁺] = [HCl] = 0.001 M
[H⁺] = 1 × 10^-3M
pH = -log[H⁺]
= -log[1 × 10^-3]
pH = 3

Question 5.
The hydrogen ion concentration of a solution is 1 × 10^-8M.
(i) What is the pH of the solution?
Answer:
pH = -log[1 × 10^-8]
pH = 8

(ii) What is the pOH of the solution?
Answer:
pOH = 14 – 8
= 6

(iii) Is the given solution acidic or basic?
Answer:
Acidic

Question 6.
Calculate the pH of 0.02 M Ba(OH)₂, Ba(OH)₂ solution is a strong electrolyte.
Answer:
[Ba(OH)₂] = 0.02 M
Ba(OH)₂ → Ba²⁺ + 2OH^–
[OH^–] = 2[Ba(OH)₂]
= 2 × 0.02 = 0.04 M
pOH = – log[0.04]
= -log[4 × 10^-2]
= -[log 4 + log 10^-2]
= -[0.6020 – 2 log 10]
pOH = -0.6020 + 2 × 1
= 1.398
pH = 14 – 1.398
= 12.602

Students can download 10th Social Science Geography Chapter 3 Components of Agriculture Questions and Answers, Notes, Samacheer Kalvi 10th Social Science Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams.

Tamilnadu Samacheer Kalvi 10th Social Science Solutions Geography Chapter 3 Components of Agriculture

Samacheer Kalvi 10th Social Science Components of Agriculture Text Book Back Questions and Answers

I. Choose the correct answer

Question 1.
The soil which is rich in iron oxides is
(a) Alluvial
(b) Black
(c) Red
(d) Alkaline
Answer:
(c) Red

Question 2.
Which of the following organization has divided the Indian soils into 8 major groups?
(a) Indian Council of Agricultural Research
(b) Indian Meteorological Department
(c) Soil Survey of India
(d) Indian Institute of Soil Science
Answer:
(a) Indian Council of Agricultural Research

Question 3.
The soils formed by the rivers are:
(a) Red soils
(b) Black soils
(c) Desert soils
(d) Alluvial soils india.
Answer:
(d) Alluvial soils india.

Question 4.
……….. dam is the highest gravity in India.
(a) Hirakud dam
(b) Bhakra Nangal dam
(c) Mettur dam
(d) Nagaijuna Sagar dam
Answer:
(b) Bhakra Nangal dam

Question 5.
……………… is a cash crop.
(a) Cotton
(b) Wheat
(c) Rice
(d) Maize
Answer:
(a) Cotton

Question 6.
Black soils are also called as ………..
(a) Arid soils
(b) Saline soils
(c) Regur soils
(d) Mountain soils
Answer:
(c) Regur soils

Question 7.
The longest dam in the world is:
(a) Mettur dam
(b) Kosi dam
(c) Hirakud dam
(d) Bhakra Nangal dam
Answer:
(c) Hirakud dam

Question 8.
The leading producer of rice in India is ……….
(a) Punjab
(b) Maharashtra
(c) Uttar Pradesh
(d) West Bengal
Answer:
(c) Uttar Pradesh

Question 9.
Which crop is called as “Golden Fibre” in India?
(a) Cotton
(b) Wheat
(c) Jute
(d) Tobacco
Answer:
(c) Jute

Question 10.
The state which leads in the production of coffee is ……….
(a) West Bengal
(b) Karnataka
(c) Odisha
(d) Punjab
Answer:
(b) Karnataka

II. Consider the given statements and choose the right option given below

Question 1.
Assertion (A): Horticulture involves the cultivation of fruits, vegetables, and flowers.
Reason (R): India ranks first in the world in the production of mango, banana, and citrus fruits.
(a) Both (A) and (R) are true and (R) explains (A)
(b) Both (A) and (R)are true: (R) does not explain (A)
(c) (A) is correct (R) is false
(d) (A) is false (R) is true
Answer:
(c) (A) is correct (R) is false

Question 2.
Assertion(A): Alluvial soil is formed by the deposition of eroded and decayed materials brought by the rivers.
Reason(R): Paddy and wheat are grown well in the soil.
(a) Both (A) and (R) are true and (R) explains (A)
(b) Both (A) and (R)are true and (R) does not explain (A)
(c) (A) is correct (R) is false
(d) (A) is false (R) is true
Answer:
(b) Both (A) and (R)are true and (R) does not explain (A)

III. Pick the odd one out

Question 1.
(a) Wheat
(b) Rice
(c) Millets
(d) Coffee
Answer:
(d) Coffee

Question 2.
(a) Khadar
(b) Bhangar
(c) Alluvial soil
(d) Black soil
Answer:
(d) Black soil

Question 3.
(a) Inundation canals
(b) Perennial canals
(c) Tanks
(d) Canals
Answer:
(c) Tanks

IV. Match the following

Answer:
A. (iv)
B. (iii)
C. (v)
D. (i)
E. (ii)

V. Answer in brief

Question 1.
Define soil.
Answer:
Soil is the uppermost layer of the land surface, usually composed of minerals, organic matter, living organisms, air and water. Its formation is mainly related to the parent rock material, surface relief, climate and natural vegetation.

Question 2.
Name the types of soil found in India.
Answer:
There are 8 major groups of soil found in India classified by the Indian Council of Agricultural Research. They are

1. Alluvial soil
2. Black soil
3. Red soil
4. Forest and Mountain soil
5. Arid and Desert soil
6. Laterite soil
7. Saline and Alkaline soil
8. Peaty and Marshy soil

Question 3.
State any two characteristics of black cotton soil.
Answer:

1. This soil is rich in calcium carbonate, magnesium, potash, lime and iron but deficient in phosphorous. It is clayey and impermeable which has great capacity to retain moisture for a long time.
2. It becomes sticky when wet but develops cracks during dry summer season. The soil is suited for dry farming due to its high moisture retentivity.

Question 4.
What is Multipurpose project?
Answer:

1. Multipurpose projects are the River valley projects.
2. Dams are constructed across rivers aims to serve many purposes such as irrigation, power generation, water supply, controlling floods, navigation, development of fisheries etc.

Question 5.
Define Agriculture.
Answer:
Agriculture is the process of producing food for people, fodder for cattle, fiber and many other desired products by the cultivation of certain plants and the raising of domesticated animals

Question 6.
State the types of agriculture practices in India?
Answer:

1. Owing to physical environment and culture the following cultivation systems prevail in India.
2. Subsistence farming
3. Intensive farming
4. Dry farming
5. Mixed farming agriculture
6. Terrace cultivation

Question 7.
Name the seasons of agriculture in India.
Answer:

1. Kharif Season
2. Rabi Season
3. Zaid Season

Question 8.
Mention the plantation crops of India.
Answer:

1. Plantation crops are mainly cultivated for the purpose of exports.
2. These crops are cultivated in large estates on hilly slopes.
3. Tea, coffee, rubber and spices are the main plantation crops of India.

Question 9.
What do you mean by livestock?
Answer:
Livestocks is defined as farm animals who are raised to generate a profile. It is an integral component of the farming system in India.

Question 10.
Write a brief note on the categories of fisheries in India?
Answer:
In India fisheries are categorised into two.They are marine or sea fisheries and inland or fresh water fisheries.

Marine or Sea fisheries:

1. It includes coastal off-shore and deep sea fishing mainly on continental shelf upto a depth of 200 mts.
2. Kerala leads in Marine fish production.

Inland or Fresh water fisheries:

1. Rivers, lakes, canals, reservoirs, ponds tanks etc are the sources of fresh water fisheries,
2. Andhra Pradesh is leading in the fresh water fisheries.
3. About 50% of the country’s total fish production comes from inland fisheries.

VI. Give reasons

Question 1.
Agriculture is the backbone of India.
Answer:
Agriculture provide food for the entire population. It supplies raw materials to the agro-based industries. It contributes to export trade. So, agriculture is the backbone of India.

Question 2.
Rain water harvesting is necessary.
Answer:
India experiences Tropical monsoon climate. Rainfall in India is seasonal, irregular and uneven and highly eractic. Hence it is necessary’ to save rain water when it is available and use in times of need. In order to prevent surface . run off Rainwater harvesting is needed.

Question 3.
Small farms are predominant in India.
Answer:
The predominant type of Indian agriculture is subsistence farming. In this agriculture land holding is small and half of the production is used for family consumption and the rest is sold in the nearby markets. The farmers concentrate on stage food crops like rice and wheat. As the farmers are poor, they can’t apply the modem inputs which cost more.

VII. Distinguish between the following

Question 1.
Rabi and Kharif crop seasons.
Answer:
Rabi crop season:

1. Rabi crop season is from October – March.
2. Seeds are sown in winter and harvested before summer.
3. Major crops of this season are mainly Wheat, Mustard, Maize etc.

Kharif crop season:

1. Kharif crop season is from June – September.
2. Seeds are sown after the summer monsoon and harvested before winter.
3. Major crops are Rice, Cotton, Groundnut, Turmeric etc.

Question 2.
Inundation canal and perennial canal.
Answer:
Inundation canal:

1. Undependable source of irrigation.
2. Operational only during flood in rivers and not have weir system to regulate water.

Perennial canal:

1. Dependable source of irrigation.
2. Have weir system through barrage to regulate water from perennial rivers or dams.

Question 3.
Marine fishing and Inland fishing.
Answer:
Marine fishing:

1. Marine fishing includes coastal, off¬shore and deep sea fishing mainly on the continental shelf upto a depth of 200m.
2. Kerala is the leading producer in marine fishing.

Inland fishing:

1. Inland fishing is done in rivers, lakes, canals, ponds, tanks, reservoirs etc.
2. Andhra Pradesh, West Bengal, Gujarat, Kerala and TamilNadu are the leading states.

Question 4.
Alluvial soils and Black soils.
Answer:
Alluvial soil:

1. Formed by the sediments deposited by the rivers and streams.
2. Silt clay, sandy and loamy in nature.
3. Found in the river valleys and plains.
4. Rice, wheat, sugarcane grow well in this soil.

Black soil:

1. Formed by the disintegration of basalt rocks.
2. Sticky when wet develops cracks when dry.
3. Found in plateau region especially in Deccan trap.
4. Cotton, sugarcane and tobacco grow well in this soil.

VIII. Answer in a paragraph

Question 1.
State the types of soil in India and explain the characteristics and distribution of soil.
Answer:

Question 2.
Write about any two multipurpose projects of India.
Answer:
A comprehensive river valley project which serves a number of purposes simultaneously is called a “Multi purposes project”.

1. The Bhakra Nangal Project: India’s biggest multipurpose river valley project is ‘Bhakra Nangal Project’. It has been built at a strategic point where two hills on either side of the Sutlej are very close to each other. It is the highest gravity dam in the world. Its length is 226 metres from the river bed. The canals taken out are 1100 kilometres long. The ‘Nangal Power Plant’ on the Sutlej produces electricity, and serves the states of Himachal Pradesh, Punjab, Haryana, Rajasthan and New Delhi. The distributaries are 8400 km in length. It irrigates an area of 1.4 million hectares.

2. Indira Gandhi Project: This project is an ambitious scheme to bring new areas under irrigation so that more areas could be cultivated. The waters of the River Beas and the Ravi are diverted to the River Sutlej. The ‘Pong’ Dam on the River Beas has been constructed to divert the Beas water into the Sutlej in a regulated manner. So that ‘Rajasthan canal’, the longest irrigation canal in the world can irrigate Gandhi Nagar, Bikaner and Jaisalmer districts of North West Rajasthan, (i.e) a part of Thar desert. The main canal now called ‘Indira Gandhi Canal’ is 468 km long runs entirely in Rajasthan, Western of Sutlej, Beas and Ravi are now being fully utilised for irrigating thirsty lands of South Western parts of our country.

Question 3.
Bring out the characteristics of intensive and Plantation farming.
Answer:
Characteristics of Intensive farming:

1. Farming is done with intensification and mechanisation system to maximize yields from available land.
2. In this farming heavy use of pesticides and chemical fertilizers have been applied.
3. It has also been applied to the raising of live stock being held indoor as factory farms.
4. Plantation fanning.
5. Single crop raised on a large area testates).
6. Crops are grown mainly for export purpose,
7. The plantations are mostly owned by companies.

Question 4.
Examine the geographical conditions favourable for the cultivation of rice and wheat.
Answer:
Rice:
Rice is an indigenous crop. India is the second-largest producer of rice in the world. It is a tropical crop which is grown well in alluvial plains and river deltas. It requires a mean monthly temperature of 24°C and an average rainfall of 150 cm and deep fertile alluvial soil for its growth. It also needs an abundant supply of cheap labour. In areas of less rainfall particularly in Punjab and Haryana, it is grown with the help of irrigation.
Rice in India is sown in three ways:

1. Broadcasting,
2. Ploughing or drilling, and
3. Transplanting.

Due to increased use of High Yielding Variety (HYV) seeds (CR Dhan 205, AR Dhan 306, CRR 451 etc.), many of the indigenous varieties were disappeared. In 2016, the first 10 leading rice-producing states are West Bengal (First in India) Uttar Pradesh, Punjab, Tamil Nadu, Andhra Pradesh, Bihar, Chhattisgarh, Odisha, Assam, and Haryana.

Wheat:
Wheat is a temperate crop. Its cultivation is mainly confined to the northwestern part of India. India produces both winter wheat and spring wheat. It is the second most important food crop of the country, after rice.

It requires 10-15°C at the time of sowing and 20-25°C at the time of ripening of grains. Over 85% of India’s wheat production comes from 5 states namely Uttar Pradesh, Punjab, Haryana, Rajasthan and Madhya Pradesh. Apart from these regions, the black soil tract of the Deccan covering parts of Maharashtra and Gujarat also contribute a major wheat production.

IX. HOTS Questions

Question 1.
Can you imagine a world without agriculture?
Answer:
Agriculture is the art and science of cultivating the soil, growing crops and raising livestock. It includes the preparation of plant and animal products for people to use and their distribution to markets.

Agriculture provides most of the world’s food and fabrics. Cotton, wool and leather are all agricultural products. It also provides wood for construction and paper products.

A world without agriculture would be very different compared to the world we live in today. It is easy for us as humans to take for granted things when we don’t really know how they are grown or produced. Without agriculture, we may not get food and clothing. Without timber, we may not be able to build houses and furniture. We may also be deprived of some everyday-products like soap, paper and ethanol, which are made up of some sort of agricultural by-product. Modern medicine also depends on agriculture. Without agriculture, we wouldn’t be here. We must always be thankful for this industry and for those involved in the various activities related to it.

Question 2.
Can you give solutions for the prevailing water disputes in South India (construction of dams / raising of dams / cleaning of tanks}?
Answer:

1. Construction of check dams: In order to prevent surface run off water • during heavy rains. Check dams has to be constructed to regulate the flow of water.
2. Raising of dams: Improves the storage capacity, Strengthening the dams is a must.
3. Cleaning of tanks: Preventing encroachment by strict legal action, desilting the tanks and deepening it in the local areas will provide water supply to the locality, as well as to maintain the areas of ground water level cleaning of tanks is a must

X. Map exercise

Question 1.
Demarcate the major tracts of alluvial soils.
Answer:

Question 2.
Delineate the main regions of black soil.
Answer:

Question 3.
Locate the Hirakud dam, Mettur dam and Damodar dam.
Answer:

Question 4.
Shade the regions of jute cultivation.
Answer:

Question 5.
Mark any three tea and coffee growing areas.
Answer:

Question 6.
Demarcate the regions of desert soil.
Answer:

Question 7.
Locate the fishing hubs: Tuticorin, Chennai,Cochin, Mumbai, Machiiipatnam
Answer:

Question 8.
Demarcate: Cauvery delta, Godavari delta.
Answer:

TB. PNo: 115
Activity 1:

Question 1.
Soil Texture (sand, silt, clay) influence on some properties of soils including water holding capacity. Find out water holding capacity of soils which given above based on following table.
Answer:

TB. PNo: 131
Activity 2:

Question 1.
Complete the following table by your day to day life experience.

Answer:

Samacheer Kalvi 10th Social Science Components of Agriculture Additional Important Questions and Answers

I. Choose the correct answer

Question 1.
……………… soil is formed by the process of leaching.
(a) Alluvial
(b) Black
(c) Laterite
(d) Arid
Answer:
(c) Laterite

Question 2.
Cotton is a ………
(a) food crop
(b) cash crop
(c) dry crop
Answer:
(b) cash crop

Question 3.
……………… is one of the method of soil conservation.
(a) Deforestation
(b) Irrigation
(c) Water logging
(d) Afforestation
Answer:
(d) Afforestation

Question 4.
The “rice bowl of Tamil nadu” is ………..
(a) Madurai
(b) Chennai
(c) Thanjavur
Answer:
(c) Thanjavur

Question 5
……………… are useful for the diversion of flood water from the rivers during rainy season.
(a) Perennial canals
(b) Inundation canals
(c) Open wells
(d) Tube wells
Answer:
(b) Inundation canals

Question 6
The type of fanning which is practised in Punjab and Haryana is ………
(a) subsistence farming
(b) commercial farming
(c) wet farming
Answer:
(b) commercial farming

Question 7.
……………… project is constructed on the river Kaveri in TamilNadu.
(a) Tehri Dam
(b) Kosi Dam
(c) Mettur Dam
(d) Horakud Dam
Answer:
(c) Mettur Dam

Question 8.
In the regions with abundant rainfall ……. is grown.
(a) millet
(b) wheat
(c) rice
Answer:
(c) rice

Question 9.
The traditional farming method that results in low productivity is:
(a) mixed farming
(b) shifting agriculture
(c) intensive farming
(d) subsistence farming
Answer:
(d) subsistence farming

Question 10.
One of the important zaid crops is ………….
(a) rice
(b) wheat
(c) watermelon
Answer:
(c) watermelon

Question 11.
First Live-stock census was conducted in India in the year:
(a) 1819
(b) 1919
(c) 1618
(d) 1981
Answer:
(b) 1919

Question 12.
The National Research Center on Plant Biotechnology was established in ………
(a) 1985
(b) 1980
(c) 1990
Answer:
(a) 1985

II. Consider the given statements and choose the right option given below

Question 1.
Assertion (A): Indian agriculture is largely dominated by food crops. Reason (R): India has a large population.
(a) Both (A) and (R) are true and (R) explains (A)
(b) Both (A) and (R)are true: (R) does not explain (A)
(c) (A) is correct (R) is false
(d) (A) is false (R) is true
Answer:
(c) (A) is correct (R) is false

Question 2.
Assertion (A): Forest and mountain soils differ from region to region. Reason (R): Due to the absence of vegetative cover.
(a) Both (A) and (R) are true and (R) explains (A)
(b) Both (A) and (R)are true: (R) does not explain (A)
(c) (A) is correct (R) is false
(d) (A) is false (R) is true
Answer:
(c) (A) is correct (R) is false
Hint: Reason is due to mechanical weathering caused by snow, rain, temperature variation depending on climate.

Question 3.
Assertion (A): Terrace farming method is practiced on hill and mountain slopes. Reason (R): The availability of land is limited and it checks soil erosion.
(a) Both (A) and (R) are true and (R) explains (A)
(b) Both (A) and (R)are true: (R) does not explain (A)
(c) (A) is correct (R) is false
(d) (A) is false (R) is true
Answer:
(a) Both (A) and (R) are true and (R) explains (A)

Question 4.
Assertion (A): Pulses are usually rotated with other crops.
Reason (R): They are used as human food and feeding cattle.
(a) Both (A) and (R) are true and (R) explains (A)
(b) Both (A) and (R) are true and (R) does not explain (A)
(c) (A) is correct (R) is false
(d) (A) is false (R) is true
Answer:
(c) (A) is correct (R) is false
Hint: They are mostly leguminous in nature and fixes atmospheric nitrogen helps soil to regain its fertility.

III. Pick the odd one out

1. (a) Tea, (b) Sugarcane, (c) Cotton, (d) Ragi
2. (a) Khandsari, (b) Herrings, (c) Mackerels, (d) Eels
3. (a) Damodhar, (b) Mahanadi, (c) Kaveri, (d) Raingun
4. (a) Water wheel, (b) Sprinkler, (c) Open well, (d) poly house
5. (a) Blue Revolution, (b) soil erosion, (c) Green Revolution, (d) Soil erosion
6. (a) Fishing, (b) Kharif, (c) Rabi, (d) Zaid

Answer:

1. (d) Ragi
2. (a) Khandsari
3. (d) Raingun
4. (c) Open well
5. (d) Soil erosion
6. (a) Fishing

IV. Match the following

Question 1.
Match the Column I with Column II.

Answer:
A. (v)
B. (i)
C. (ii)
D. (iii)
E. (iv)

Question 2.
Match the Column I with Column II.

Answer:
A. (ii)
B. (iv)
C. (v)
D. (i)
E. (iii)

Question 3.
Match the Column I with Column II.

Answer:
A. (vi)
B. (iii)
C. (ii)
D. (i)
E. (iv)
F. (v)

V. Answer in brief

Question 1.
Why is tank irrigation more prevalent in South India than North India?
Answer:
The undulated topography of peninsular region forms large depressions to collect water which become tanks. So the tank irrigation is more prevalent in South India than North India.

Question 2.
How laterite soils are formed?
Answer:
Laterite soils are formed in the regions where alternate wet and dry conditions prevail.
It is formed by the process of leaching.

Question 3.
Which is an acute problem in India? How?
Answer:
Soil degradation is an acute problem in India. According to a 2015 report of the Indian institute of remote sensing (IIRS). The estimated the amount of soil .erosion that occurred in India was 147 million hectares.
The main problems of the Indian soils are

1. Soil erosion
2. Degradation of Soil
3. Water-logging
4. Saline and Alkaline and
5. Salt Flats.

Question 4.
Draw a flow chart showing the sources of irrigation and their classification.
Answer:

Question 5.
Write few lines about Rain Gun.
Answer:
It is used to spread water like rain and used to serve for crops which used to grow up to 4 feet or high also but we have to adjust sprinklers height as per crop size, typical usage of Rain guns are in sugarcane, maize crops.

Question 6.
Name the food crops grown in India.
Answer:
Food crops that are grown in India include cereals and pulses amongst which rice, wheat, jowar, bajra, maize, barely, ragi, gram and tur are important.

Question 7.
Give short notes about Terrace cultivation.
Answer:
This is practised especially in hilly areas, where lands are of sloping nature. The hill and mountains slopes are cut to form terraces and the land is used in the same way as in permanent agriculture.

Question 8.
Name the five leading states that contribute 85% of India’s wheat production.
Answer:
Uttar Pradesh, Punjab, Haryana, Rajasthan and Madhya Pradesh are the leading states in wheat production in India.

Question 9.
What are the products of Sugarcane?
Answer:
Sugarcane provides raw material for the sugar industry. Besides providing sugar, gur and Khandsari it supplies molasses for alcohol industry and bagasse for paper industry.

Question 10.
How jute is useful for trade?
Answer:

1. Jute fibre provides raw material for Jute industry.
2. It is used for manufactruing of gunny bags, carpets, hessian, ropes and strings, rugs, clothes, tarpaulins, upholstery etc.

Question 11.
What is the other name of ‘Shifting Agriculture1? Who practice shifting agriculture? and how it is called in different regions?
Answer:
‘Shifting Agriculture’ is also called as ‘Slash and bum’ Agriculture. The tribal people follow this type of agriculture. It is called by different names in different regions in India as follows.

Question 12.
What is dry farming?
Answer:
Dry farming is the type of farming practiced in arid areas where there is lack of irrigation facilities. Crops grown in these areas can withstand dry conditions.

Question 13.
What are called cash crops? Give examples.
Answer:
Crops which are cultivated for commercial purpose are called cash crops, eg: Sugarcane, tobacco, fibre crops and oil seeds.

Question 14.
Which is the largest oil seeds producing state? What is the position of India in oil seeds production in the world?
Answer:
Gujarat is India’s largest oil seeds producing state. India is the second largest producer of oil seeds in the world next to China.

Question 15.
Define Green Revolution.
Answer:
The process of improving and increasing the production of food crops using modem techniques is referred as Green Revolution.

Question 16.
Mention the different breeds of cattle population in India.
Answer:
Cattle population in India belongs to different breeds. They are

1. Milch breed
2. Draught breed
3. Mixed or General breed

VI. Give Reasons

Question 1.
Tank irrigation is popular in peninsular India.
Answer:
The undulating relief, absence of perennial rivers, Impermeable rock structure and natural depression are the reasons for having tank irrigation most popular in Peninsular India.

Question 2.
Why tea is grown on the hill slopes?
Answer:
Tea plants require high rainfall but its roots cannot tolerate water logging. Frost condition is a must for tea plants. So it is grown on the hill slopes.

Question 3.
Inundation canals are not dependable source of irrigation.
Answer:
Inundation canals are operational only during rainy season for the diversion of flood water directly from the rivers. Hence these canals are not dependable source of irrigation.

Question 4.
Shifting agriculture is also called as slash and burn agriculture.
Answer:
Once the forest land piece is cleared by tribal people they grow crops for two to three years and bum the stumps after harvest and abandoning the lands to regain its fertility and then move to new areas. Thus, shifting agriculture is also called ‘slash and bum’ agriculture.

Question 5.
Only little surplus is left in subsistence farming.
Answer:
Mainly in subsistence farming crops are grown for family consumption leaving little surplus to sell in the market. Preference will be given to food crops as per their needs.

Question 6.
Indian agriculture is mainly dominated by the food crops.
Answer:
As the population increases the need for food also increase. Due to the need and to supply to the large population Indian agriculture is mainly dominated by the food crops.

VII. Distinguish between the following

Question 1.
Laterite and Red soil.
Solution:
Laterite soil:

1. Femed by the process of leaching under wet and hot dry conditions.
2. Mainly composed of hydrated oxides of iron and aluminium.
3. Found mostly on hilly areas.
4. Suitable for tea, coffee, rubber and cashewnut.

Red soil:

1. Formed by the decomposition of ancient crystalline rocks.
2. Rich in minerals like iron and magnesium.
3. Found in plateau regions.
4. Suitable for pulses and sugarcane.

Question 2.
Arid and desert soil and Peaty and marshy soil.
Answer:
Arid and Desert soil:

1. Formed due to dry climate and high temperature.
2. Poor in organic matter and nitrogen rich in salt content.
3. Found in Rajasthan Northern Gujarat and Southern Punjab.
4. Millets, barley and pulses grow with irrigation.

Peaty and Marshy soil:

1. Formed in humid regions from organic matter.
2. Poor in potash and phosphate rich in vegetable organic matter.
3. Found in coastal areas and Sunderban Deltaic region, Kerala, Odisha, West Bengal.
4. Ideal for paddy and Jute cultivation.

Question 3.
Open well and Tube well irrigation.
Answer:
Open well irrigation:

1. Need sufficient ground water availability.
2. Practiced in areas of Ganga plains and river Deltaic regions.

Tube well irrigation:

1. Can be found in areas of low water table and soft geological subsurface.
2. Need sufficient water supply. Predominant in the states of Gujarat, Maharashtra, Madhya Pradesh and TamilNadu.

Question 4.
Bhakra Nangal and Hirakud project.
Answer:
Bhakra Nangal Project:

1. Constructed on the river Sutlej.
2. Highest gravity dam in the world.
3. Punjab, Haryana and Rajasthan states are benefitted.

Hirakud Project:

1. Constructed on the river Mahanadhi.
2. Longest dam in the world.
3. State of Odhisha is benefitted by this project.

Question 5.
Subsistence and Mixed farming.
Answer:
Subsistence farming:

1. Crops is mainly cultivated for family consumption.
2. Traditional farming methods are used due to small land holdings.
3. Mainly concentrated on food crops.

Mixed farming:

1. Integrated farming to satisfy many needs of the farmers.
2. Modem techniques is used for crop cultivation done in a vast area.
3. System include crop production along with raising live stock, poultry, fisheries, bee keeping etc.

Question 6.
Food and Cash crops.
Answer:
Food crops:

1. Mainly grown for consumption purpose.
2. Food crops include rice, wheat, pulses etc.
3. Apart from consumption used as raw materials for agro based industries.

Cash crops:

1. Crops are cultivated for commercial purpose.
2. Sugarcane, cotton, jute, oil seeds are the main cash crops. .
3. Mainly produced for raw materials for industries and earn valuable foreign exchange.

Question 7.
Rice and Wheat.
Answer:
Rice:

1. Mainly Tropical crop.
2. Need abundant supply of water till harvest.
3. West Bengal, Uttar Pradesh, Punjab, TamilNadu, Andhra Pradesh are some of the leading states in Rice production.

Wheat:

1. Sub tropical or Temperate crop.
2. Need moderate water supply.
3. Uttar Pradesh, Punjab, Haryana, Rajasthan and Madhya Pradesh are the leading states in wheat production.

VIII. Answer in a paragraph

Question 1.
What is a multipurpose project and explain its purpose?
Answer:
A comprehensive river valley project which serves a number of purposes simultaneously is called a “Multipurpose project”. Multipurpose projects serve the following purposes.

1. They help to store water, that can be utilised, when water, is in great demand both for agricultural and domestic purpose.
2. They check floods and famines.
3. Afforestation is undertaken in the catchment areas of river, which helps conservation of water, soil and wildlife. Thus it keeps ecosystem intact.
4. Production of hydro electricity is also another purpose of these projects. It is a pollution free of energy and is renewable energy.
5. They attract tourists and develops tourism industry.
6. Soil conservation and land relamation are other purpose of these projects.

Question 2.
What do you mean by Irrigation? Why it is necessary in India?
Answer:

1. Watering to agricultural lands by artificial means for cultivation is called Irrigation.
2. India is a tropical monsoon country.
3. 75% of rainfall is received within a span of four months.
4. Indian rainfall from monsoons are seasonal, uneven, irregular and erratic in nature.
5. So always there is a need for irrigation to carry out agricultural activities during dry period.
6. Besides erratic rainfall prevalence of high temperature, cultivation of annual crops and hydrophytes.
7. Commercial farming and porous soil make irrigation an essential one for agriculture in India.

Question 3.
What are the different sources of irrigation used in different parts of India?
Answer:
The main sources of irrigations are
1. Canal irrigation
2. Well irrigation
3. Tank irrigation

1. Canal irrigation:
It is the second most important sources of irrigation in India. The Canals are of two types.
i. Inundation canals
ii. Perennial canals

i. Inundation canals:
In this, water is taken directly from the rivers without making any kind of barrage or dam. Such canals are useful for the diversion of flood water from the rivers and remains operational during rainy season.

ii. Perennial canals:
These are developed from perennial work by constructing barrage to regulate the flow of water. These canals are useful for irrigation.

2. Well irrigation:
A Well is a hole or trough usually vertical excavated in the earth for brining groundwater to the surface. It contributes about 62% of net irrigated area in India. Wells are of two types.
i. Open well
ii. Tube well

i. Open well:
This type of irrigation is widely practiced in the areas where groundwater is sufficiently available. The areas are in Ganga plains, the deltaic region of Mahanadi, Godavari, Krishna, Cauvery and parts of Narmada and Tapti valleys.

ii. Tube well:
Tube wells are developed in the areas of low water table, sufficient power supply and soft subsurface geological units. Tube wells are predominant in the states of Gujarat, Maharashtra, Punjab, MP, and Tamil Nadu.

3. Tank irrigation:
A tank is a natural or man-made hollow on the surface developed by constructing a small bund around it across a stream It is used to collect and store water for irrigation and other purpose. It also includes irrigation from taken and ponds.

Question 4.
How is Live-stock census conducted in TamilNadu?
Answer:
State Government is conducting Live stock census with the help of:

1. Department of Animal Husbandary at State level and
2. Regional Joint Director at District level under the guidelines of Government of India ministry of Agriculture and farmers welfare,
3. Department of Animal husbandary, Dairying and Fisheries conducted once in 5 years.

Question 5.
Explain about the major issues faced by the Indian farmers?
Answer:
We can divide the problems faced by the Indian agriculture and by the farmers into two Natural and Man made.
Natural problems:

1. Soil erosion: Large tracts of land suffer from soil erosion by wind and water.
2. Infertile soil: Growing crops for many years without replenishing led to the exhaution of soil and its depletion.
3. Lack of Irrigation: Only some areas of the cropped falls under irrigation.

Man made problems:

1. Small land holdings and fragmented land: Poor status made the farmers to have small land and also some farmers possesses share from their ancestral property cannot afford to apply mechanism.
2. High costs of Inputs: Good quality of seeds are out of reach for many small and marginal farmers due to their high price.
3. Agricultural marketing: Absence of sound marketing, facility, interference of local traders and middlemen for the disposal of their produce, fluctuations in the price.
4. In adequate transport: Lakhs of villages are not w7ell connected with main roads or with market centres. Lack of cheap and efficient means of transportation is not available.
5. Scarcity of capital: Huge capital is needed to purchase advanced farm machineries and equipments which the poor farmers cannot afford to buy.

Question 6.
List out some of the Agricultural Revolutions in India.
Answer:

Question 7.
“Per Drop more Crop”. Explain this statement.
Answer:

1. It is the scheme introduced by the Government of India with the objective to enhance water use efficiency.
2. This micro irrigation scheme comes under “Pradhan Mantri Krishi Sinchayee Yojana (PMKSY) and centrally sponsored scheme on micro irrigation.
3. It promotes appropriate technological interventions like drop and sprinkler irrigation technologies in agriculture and encourage farmers to use water saving and conservation technique.
4. Following five states progressed 78% under micro irrigation scheme
   • Andhra Pradesh
   • Karnataka
   • Gujarat
   • Maharashtra
   • TamilNadu

IX. Map Questions
Mark the following on the outline map of India.

Question 1.
Areas of Red soil and Mountain soil.
Answer:

Question 2.
Demarcate the states producing the highest for the following crops.
Answer:
(i) Paddy

(ii) Sugarcane

(iii) Cotton

(iv) Wheat

Question 3.
Kosi project, Tungabadra, Periyar Dam, Nagarjuna Sagar.
Answer:

Students can download 10th Science Chapter 11 Carbon and its Compounds Questions and Answers, Notes, Samacheer Kalvi 10th Science Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams.

Tamilnadu Samacheer Kalvi 10th Science Solutions Chapter 11 Carbon and its Compounds

Samacheer Kalvi 10th Science Carbon and its Compounds Text Book Back Questions and Answers

I. Choose the best answer:

Question 1.
The molecular formula of an open-chain organic compound is C₃H₆. The class of the compound is:
(a) alkane
(b) alkene
(c) alkyne
(d) alcohol
Answer:
(b) alkene

Question 2.
The IUPAC name of an organic compound is 3-Methyl butan-1-ol. What type of compound it is?
(a) Aldehyde
(b) Carboxylic acid
(c) Ketone
(d) Alcohol
Answer:
(d) Alcohol

Question 3.
The secondary suffix used in IUPAC nomenclature of an aldehyde is:
(a) – ol
(b) – oic acid
(c) – al
(d) – one
Answer:
(c) – al

Question 4.
Which of the following pairs can be the successive members of a homologous series?
(a) C₃H₈ and C₄H₁₀
(b) C₂H₂ and C₂H₄
(c) CH₄ and C₃H₆
(d) C₂H₅OH and C₄H₈OH.
Answer:
(a) C₃H₈ and C₄H₁₀
Hint: Two successive members of a homologous series must have a difference of -CH₂ in the molecular formula.
\(\mathrm{C}_{3} \mathrm{H}_{8} \stackrel{+\mathrm{CH}_{2}}{\longrightarrow} \mathrm{C}_{4} \mathrm{H}_{10}\).

Question 5.
C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O is a:
(a) Reduction of ethanol
(b) Combustion of ethanol
(c) Oxidation of ethanoic acid
(d) Oxidation of ethanal
Answer:
(b) Combustion of ethanol

Question 6.
Rectified spirit is an aqueous solution which contains about ______ of ethanol.
(a) 95.5 %
(b) 75.5 %
(c) 55.5 %
(d) 45.5 %.
Answer:
(a) 95.5 %
Rectified spirit is a mixture of 95.5 % of ethanol and 4.5 % of water.

Question 7.
Which of the following are used as anaesthetics?
(a) Carboxylic acids
(b) Ethers
(c) Esters
(d) Aldehydes
Answer:
(b) Ethers

Question 8.
TFM in soaps represents _____ content in soap.
(a) mineral
(b) vitamin
(c) fatty acid
(d) carbohydrate.
Answer:
(c) fatty acid
Hint: TFM – Total Fatty Matter. It corresponds the fatty acid (oil).

Question 9.
Which of the following statements is wrong about detergents?
(a) It is a sodium salt of long chain fatty acids
(b) It is sodium salts of sulphonic acids
(c) The ionic part in a detergent is – SO₃ ^–Na⁺
(d) It is effective even in hard water.
Answer:
(a) It is a sodium salt of long-chain fatty acids

II. Fill in the blanks:

1. An atom or a group of atoms which is responsible for chemical characteristics of an organic compound is called …………
2. The general molecular formula of alkynes is ………..
3. In IUPAC name, the carbon skeleton of a compound is represented by ………. (root word / prefix / suffix)
4. (Saturated / Unsaturated) ……….. compounds decolourize bromine water.
5. Dehydration of ethanol by cone. Sulphuric acid forms ………. (ethene/ ethane)
6. 100 % pure ethanol is called ………..
7. Ethanoic acid turns ………… litmus to …………
8. The alkaline hydrolysis of fatty acids is termed as …………
9. Biodegradable detergents are made of …………. (branched / straight) chain hydrocarbons.
Answer:
1. Functional group
2- C_nH_2n-2
3. root word
4. unsaturated
5. ethene
6. absolute alcohol
7. Blue, red
8. Saponification
9. straight

III Match the following:

Question 1.
Match the Column I and Column II.

Answer:
A. (iii)
B. (iv)
C. (v)
D. (ii)
E. (i)

IV. Assertion and Reason:

Answer the following questions using the data given below:
Question 1.
Assertion: Detergents are more effective cleansing agents than soaps in hard water.
Reason: Calcium and magnesium salts of detergents are water soluble.
(a) Assertion and Reason are correct, Reason explains the Assertion.
(b) Assertion is correct, Reason is wrong.
(c) Assertion is wrong, Reason is correct.
(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.
Answer:
(a) Assertion and Reason are correct, Reason explains the Assertion.

Question 2.
Assertion: Alkanes are saturated hydrocrabons.
Reason: Hydrocarbons consits of covalnet bonds.
(a) Assertion and Reason are correct, Reason explains the Assertion .
(b) Assertion is correct, Reason is wrong.
(c) Assertion is wrong, Reason is correct.
(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.
Answer:
(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.

V. Short answer questions:

Question 1.
Name the simplest ketone and give its structural formula.
Answer:
The simplest ketone is Propanone.
It’s structural formula:

Question 2.
Classify the following compounds based on the pattern of carbon chain and give their structural formula:
(i) Propane
(ii) Benzene
(iii) Cyclo butane
(iv) Furan.
Answer:

Question 3.
How is ethanoic acid prepared from ethanol? Give the chemical equation.
Answer:
Ethanol is oxidized to ethanoic acid with alkaline KMnO₄ or acidified K₂Cr₂O₇.

Question 4.
How do detergents cause water pollution? Suggest remedial measures to prevent this pollution?
Answer:

• Some detergents having a branched hydrocarbon chain are not fully biodegradable by microorganisms present in water. So, they cause water pollution.
• They have straight hydrocarbon chains, in biodegradable detergents, which can be easily degraded by bacteria.

Question 5.
Differentiate soaps and detergents.
Answer:

VI. Long answer questions.

Question 1.
What is called a homologous series? Give any three of its characteristics?
Answer:
A homologous series is a group or a class of organic compounds having the same general formula and similar chemical properties in which the successive members differ by a – CH₂ group.
Characteristics of homologous series:

• All members of a homologous series contain the same elements and functional group.
• All members of a homologous series can be prepared by a common method.
• Chemical properties of the members of a homologous series are similar.

Question 2.
Arrive at, systematically, the IUPAC name of the compound: CH₃-CH₂– CH₂-OH.
Answer:
Step 1: The parent chain consists of 3 carbon atoms. The root word is ‘Prop’.
Step 2: There are single bonds between the carbon atoms of the chain. So, the primary suffix is ‘ane’.
Step 3: Since, the compound contains – OH group, it is an alcohol. The carbon chain is numbered from the end which is closest to – OH group. (Rule 3)

Step 4: The locant number of – OH group is l and thus the secondary suffix is ‘l-ol’.
The name of the compound is Prop + ane + (l – ol) = Propan-l-ol

Question 3.
How is ethanol manufactured from sugarcane?
Answer:
Ethanol is manufactured in industries by the fermentation of molasses, which is a by-product obtained during the manufacture of sugar from sugarcane. Molasses is a dark coloured syrupy liquid left after the crystallization of sugar from the concentrated sugarcane juice. Molasses contain about 30% of sucrose, which cannot be separated by crystallization. It is converted into ethanol by the following steps:
(i) Dilution of molasses : Molasses is first diluted with water to bring down the concentration of sugar to about 8 to 10 percent.

(ii) Addition of Nitrogen source : Molasses usually contains enough nitrogenous matter to act as food for yeast during the fermentation process. If the nitrogen content of the molasses is poor, it may be fortified by the addition of ammonium sulphate or ammonium phosphate.

(iii) Addition of YeastrThe solution obtained in step (ii) is collected in large ‘fermentation tanks’ and yeast is added to it. The mixture is kept at about 303K for a few days. During this period, the enzymes invertase and zymase present in yeast, bring about the conversion of sucrose into ethanol.

The fermented liquid is technically called wash.

(iv) Distillation of ‘Wash’: The fermented liquid (i.e., wash), containing 15 to 18 percent alcohol, is now subjected to fractional distillation. The main fraction drawn is an aqueous solution of ethanol which contains 95.5% of ethanol and 4.5% of water. This is called rectified spirit. This mixture is then refluxed over quicklime for about 5 to 6 hours and then allowed to stand for 12 hours. On distillation of this mixture, pure alcohol (100%) is obtained. This is called absolute alcohol.

Question 4.
Give the balanced chemical equation of the following reactions:
(i) Neutralization of NaOH with ethanoic acid.
Answer:

(ii) Evolution of carbon dioxide by the action of ethanoic acid with NaHCO₃.
Answer:

(iii) Oxidation of ethanol by acidified potassium dichromate.
Answer:

(iv) Combustion of ethanol.
Answer:

Question 5.
Explain the mechanism of cleansing action of soap.
Answer:
A soap molecule contains two chemically distinct parts that interact differently with water. It has one polar end, which is a short head with a carboxylate group (-COONa) and one non – polar end having the long tail made of the hydrocarbon chain.

The polar end is hydrophilic (Water-loving) in nature and this end is attracted towards the water. The non – polar end is hydrophobic (Water hating) in nature and it is attracted towards dirt or oil on the cloth, but not attracted towards the water. Thus, the hydrophobic part of the soap molecule traps the dirt and the hydrophilic part makes the entire molecule soluble in water.

When soap or detergent is dissolved in water, the molecules join together as clusters called ‘micelles’. Their long hydrocarbon chains attach themselves to the oil and dirt. The dirt is thus surrounded by the non-polar end of the soap molecules. The charged carboxylate end of the soap molecules makes the micelles soluble in water. Thus, the dirt is washed away with the soap.

VII. Hot Questions.

Question 1.
The molecular formula of an alcohol is C₄H₁₀O. The locant number of its -OH group is 2.
(i) Draw its structural formula.
Answer:

(ii) Give its IUPAC name.
Answer:
Butan-2-ol

(iii) Is it saturated or unsaturated?
Answer:
Saturated

Question 2.
An organic compound ‘A’ is widely used as a preservative and has the molecular formula C₂H₄O₂. This compound reacts with ethanol to form a sweet smelling compound ‘B’.
(i) Identify the compound ‘A’.
Answer:
Organic Compound ‘A’ with the molecules formula C₂ H₄ O₂ which is a preservative is acetic acid (or) ethanoic acid.
A – CH₃COOH

(ii) Write the chemical equation for its reaction with ethanol to form compound ‘B’.
Answer:

B – Ethyl ethanoate (ester – sweet smelling)

(iii) Name the process.
Answer:
Esterification

Samacheer Kalvi 10th Science Carbon and its Compounds Additional Important Questions and Answers

I. Choose the best answer.

Question 1.
The general formula of alkane series is:
(a) C_nH_2n
(b) C_nH_2n-1
(C) C_nH_2n+2
(d) C_nH_2n-2
Answer:
(C) C_nH_2n+2

Question 2.
Organic compounds are _____ in nature.
(a) flammable
(b) inflammable
(c) heavy
(d) light.
Answer:
(b) inflammable

Question 3.
The Heterocyclic compound is:
(a) Benzene
(b) Pyridine
(c) Naphthalene
(d) Camphor
Answer:
(b) Pyridine

Question 4.
Pick out the unsaturated compound from the following ______.
(a) CH₃ – CH₂ – CH₃
(b) CH₃ – CH = CH₂
(c) \(\mathrm{CH}_{3}-\mathrm{C} \equiv \mathrm{CH}\)
(d) both (b) and (c).
Answer:
(d) both (b) and (c).

Question 5.
……….. will decolourise Br₂/H₂O.
(a) Methane
(b) Pent-2-ene
(c) Ethyl alcohol
(d) Ethanal
Answer:
(b) Pent-2-ene

Question 6.
The simplest alkane is ______.
(a) Ethane
(b) Ethyne
(c) Propane
(d) Methane.
Answer:
(d) Methane.

Question 7.
……….. is the prefix used for -NH₂ Group.
(a) Fluoro
(b) Methyl
(c) Amino
(d) Nitro
Answer:
(c) Amino

Question 8.
The IUPAC name of an organic compound is Pentan-2-one. The secondary suffix is:
(a) Pentan
(b) an
(c) -one
(d) -2-
Answer:
(c) -one

Question 9.
Molasses is fortified with ………… to increase the nitrogen content.
(a) (NH₄)₂SO₄ (or) (NH₄)₃PO₄
(b) (NH₄)₂CO₃ (or) NH₄Cl
(c) (NH₄)₂CO₃ (or) NH₄OH
(d) None of the above
Answer:
(a) (NH₄)₂SO₄ (or) (NH₄)₃PO₄

Question 10.
Which one of the following is a general formula for alkyne?
(a) C_nH_2n
(b) C_nH_2n+2
(c) C_nH_2n-2
(d) C_nH_n
Answer:
(c) C_nH_2n-2

II. Fill in the blanks.

1. The common difference between the successive member of the homologous series if ……….. group.
2. Denatured spirit is a mixture of ethanol and …………
3. Methane gas is produced when the sodium salt of ethanoic acid is ………… with soda lime.
4. For coagulating rubber from latex ………… is used.
5. ………… is added to prevent the caking of the detergent powder.
6. When a soap or detergent is added to water the moleculer cluster together to form ……….
7. The terminal functional group among aldehydes and ketones is ………..
8. On dehydrogenation of ethanol with Cu/573 K it gives ………… gas.
9. ……… converts glucose into ethanol and carbondi-oxide.
10. The structural formula of Pentanoic acid is …………
Answer:
1. -CH₂
2. pyridine
3. decarboxylated
4. ethanoic acid
5. Na₂SO₄ or Sodium sulphate
6. micelles
7. aldehyde
8. H₂
9. Zymase
10. CH₃CH₂CH₂CH₂COOH

III Match the following:

Question 1.
Match the column I and column II.

Answer:
A. (ii)
B. (iii)
C. (v)
D. (i)
E. (iv)

Question 2.
Match the column I and column II.

Answer:
A. (v)
B. (iv)
C. (i)
D. (iii)
E. (ii)

IV Assertion and Reason.

Answer the following questions using the data given below:
Question 1.
Assertion: Alkynes decolourise bromine water.
Reason: Alkynes are unsaturated compounds.
(a) Assertion and Reason are correct, Reason explains Assertion.
(b) Assertion is correct, Reason is wrong.
(c) Assertion is wrong, Reason is correct.
(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.
Answer:
(a) Assertion and Reason are correct, Reason explains Assertion.

Question 2.
Assertion: Denaturation of ethanol makes it unfit for drinking purpose.
Reason: Ethanol is mixed with Pyridine for denaturation.
(a) Assertion and Reason are correct, Reason explains Assertion.
(b) Assertion is correct, Reason is wrong.
(c) Assertion is wrong, Reason is correct.
(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.
Answer:
(a) Assertion and Reason are correct, Reason explains Assertion.

Question 3.
Assertion: Organic compounds contains covalent bond.
Reason: Organic compounds have low melting and boiling points.
(a) Assertion and Reason are correct, Reason explains Assertion.
(b) Assertion is correct, Reason is wrong.
(c) Assertion is wrong, Reason is correct.
(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.
Answer:
(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.

Question 4.
Assertion: Due to catenation a large number of carbon compounds are formed.
Reason: Carbon compounds show the property of allotropy.
(a) Assertion and Reason are correct, Reason explains Assertion.
(b) Assertion is correct, Reason is wrong.
(c) Assertion is wrong, Reason is correct.
(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.
Answer:
(b) Assertion is correct, Reason is wrong.

V. Short answer questions:

Question 1.
Define isomerism with an example.
Answer:
Isomerism is a phenomenon in which organic compounds having the same molecular formula will have different structural formula.
Eg: for the molecular formula C₂H₆O we can write
CH₃CH₂OH – ethanol
CH₄O CH₃ – Methoxy methane

Question 2.
What are root words?
Answer:
Root words are the basic unit which describes the carbon skeleton. It gives the number of carbon atoms present in the parent chain of the compound and the pattern of their arrangement.

Question 3.
Write The functional group and the secondary suffix of the following compounds.
Answer:

Question 4.
What happens when ethanol is dehydrated with con.H₂SO₄ at 443K?
Answer:
Dehydration (Loss of water): When ethanol is heated with cone. H₂SO₄ at 443K, it loses a water molecule i.e., dehydrated to form ethene.

Question 5.
Write a note on esterification.
Answer:
The reaction of an alcohol with a carboxylic acid gives a compound having fruity odour. This compound is called an ester and the reaction is called esterification. Ethanol reacts with ethanoic acid in the presence of cone. H₂SO₄ to form ethyl ethanoate, an ester.

Question 6.
Write tests to identify the presence of ethanoic acid.
Answer:

1. Ethanoic acid turns blue litmus paper to red.
2. Ethanoic acid gives brisk effervescence when treated with Na₂CO₃
3. Ethanoic acid gives a sweet-smelling compound called ester when treated with ethanol.

Question 7.
Write a note on decarboxylation reaction.
Answer:
Decarboxylation (Removal of CO₂): When a sodium salt of ethanoic acid is heated with soda lime (solid mixure of 3 parts of NaOH and 1 part of CaO), methane gas is formed.

Question 8.
What is hard soap?
Answer:
Soaps, which are prepared by the saponification of oils or fats with caustic soda (sodium hydroxide), are known as hard soaps. They are usually used for washing purposes.

Question 9.
Why ordinary soap is not suitable for using with hard water?
Answer:
Ordinary soaps when treated with hard water, precipitate as salts of calcium and magnesium. They appear at the surface of the cloth as sticky grey scum. Thus, the soaps cannot be used conveniently in hard water.

Question 10.
What are the advantages of detergents over soaps?
Answer:
Detergents are better than soaps because of they:

1. can be used in both hard and soft water and can clean more effectively in hard water than soap.
2. can also be used in saline and acidic water.
3. do not leave any soap scum on the tub or clothes.
4. dissolve freely even in cool water and rinse freely in hard water.
5. can be used for washing woollen garments, whereas soap cannot be used.
6. have a linear hydrocarbon chain, which is biodegradable.
7. are active emulsifiers of motor grease.
8. do an effective and safe cleaning, keeping even synthetic fabrics brighter and whiter.

VI. Long answer questions.

Question 1.
Write the IUPAC name of the following compounds
Answer:

Question 2.
Write the characteristics of organic compounds.
Answer:

1. Organic compounds have a high molecular weight and a complex structure.
2. They are mostly insoluble in water but soluble in organic solvents such as ether, carbon tetrachloride, toluene, etc.
3. They are highly inflammable in nature.
4. Organic compounds are less reactive compared to inorganic compounds. Hence, the reactions involving organic compounds proceed at slower rates.
5. Mostly organic compounds form covalent bonds in nature.
6. They have a lower melting point and boiling point when compared to inorganic compounds
7. They exhibit the phenomenon of isomerism, in which a single molecular formula represents several organic compounds that differ in their physical and chemical properties
8. They are volatile in nature.
9. Organic compounds can be prepared in the laboratory.

Question 3.
List the advantages of detergents over soaps.
Answer:

1. Can be used in both hard and soft water and can clean more effectively in hard water than soap.
2. Can also be used in saline and acidic water.
3. Do not leave any soap scum on the tub or clothes.
4. Dissolve freely even in cool water and rinse freely in hard water.
5. Can be used for washing woollen garments, where as soap cannot be used.
6. Have a linear hydrocarbon chain, which is biodegradable.
7. Are active emulsifiers of motor grease.
8. Do an effective and safe cleansing, keeping even synthetic fabrics brighter and whiter.

Question 4.
Draw the schematic diagram for the classification of organic compounds based on the pattern of carbon chain with example.
Answer:

Question 5.
Explain the manufacture of soap.
Answer:
Manufacture of soap by Kettle Process This is the oldest method. But, it is still widely used in the small scale preparation of soap. There are mainly, two steps to be followed in this process.

1. Saponification of oil: The oil, which is used in this process, is taken in an iron tank (kettle). The alkaline solution (10%) is added into the kettle, a little in excess. The mixture is boiled by passing steam through it. The oil gets hydrolysed after several hours of boiling. This process is called Saponification.

2. Salting out of soap: Common salt is then added to the boiling mixture. Soap is finally precipitated in the tank. After several hours the soap rises to the top of the liquid as a ‘curdy mass’. The neat soap is taken off from the top. It is then allowed to cool down.

Question 6.
Ethanol is heated with excess con.H₂SO₄ at 443K.
(a) Name the reaction that occurs and explain it.
Answer:
Dehydration (Loss of water).
When ethanol is heated with conc.H₂SO₄ at 443K, it loses a water molecule i.e., dehydrated to form ethene.

Answer:

(c) What is the product formed? What happen when this gas is passed through Br₂/H₂O.
Answer:
Ethene gas.
When it is passed through Br₂/H₂O it gets decolourised because it is an unsaturated compound.

(d) Why does no decolonization occurs when ethanol is treated with Br₂/H₂O?
Answer:
Ethanol is a saturated compound. Therefore no decolourisation occurs.

VII. Hot Questions.

Question 1.
Organic compounds A and B are isomers with the molecular formula C₂H₆O (A) liberates H2 gas when it reacts with metallic sodium whereas (B) does not. Compound (A) reacts with ethanoic acid and forms a fruity smelling compound (C). Identify A, B and C and explain the reactions.
Answer:
(A) and (B) are compounds with same molecular formula C₂H₆O.
(A) reacts with metallic Na and liberates H₂↑
∴ (A) is ethanol [CH₃CH₂OH]
(B) is methoxy methane [CH₃OCH₃]

(A) reacts with ethanoic acid and forms ester.

(A) Ethanol, CH₃CH₂OH
(B) Methoxy methane, CH₃OCH₃
(C) Ethyl ethanoate, CH₃COOC₂H₅

Question 2.
Write the IUPAC names of the following compounds.
Answer:

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Tamilnadu Samacheer Kalvi 10th Social Science Solutions History Chapter 4 The World after World War II

Samacheer Kalvi 10th Social Science The World after World War II Text Book Back Questions and Answers

I. Choose the correct answer

Question 1.
Who was the first director of Whampoa Military Academy?
(a) Sun Yat-Sen
(b) Chiang Kai-Shek
(c) Michael Borodin
(d) Chou En Lai
Answer:
(b) Chiang Kai-Shek

Question 2.
Which American President followed the policy of containment of Communism?
(a) Woodrow Wilson
(b) Truman
(c) Theodore Roosevelt
(d) Franklin Roosevelt
Answer:
(b) Truman

Question 3.
When was People’s Political Consultative Conference held in China?
(a) September 1959
(b) September 1948
(c) September 1954
(d) September 1949
Answer:
(d) September 1949

Question 4.
The United States and European allies formed to resist any Soviet aggression in Europe.
(a) SEATO
(b) NATO
(c) SENTO
(d) Warsaw Pact
Answer:
(b) NATO

Question 5.
Who became the Chairman of the PLO’s Executive Committee in 1969?
(a) Hafez al-Assad
(b) Yasser Arafat
(c) Nasser
(d) Saddam Hussein
Answer:
(b) Yasser Arafat

Question 6.
When was North and South Vietnam united?
(a) 1975
(b) 1976
(c) 1973
(d) 1974
Answer:
(b) 1976

Question 7.
Where was Arab League formed?
(a) Cairo
(b) Jordan
(c) Lebanon
(d) Syria
Answer:
(a) Cairo

Question 8.
When was the Warsaw Pact dissolved?
(a) 1979
(b) 1989
(c) 1990
(d) 1991
Answer:
(d) 1991

II. Fill in the blanks

1. ………………. was known as the “Father of modern China”.
2. in 1918, the society for the study of Marxism was formed in ………………. University.
3. After the death of Dr. Sun Yat-Sen, the leader of the Kuomintang party was ……………….
4. ……………….. treaty is open to any Arab nation desiring peace and security in the region.
5. The treaty of ………………. provided for mandates in Turkish -Arab Empire.
6. Germany joined the NATO in ……………….
7. ………………. was the Headquarters of the Council of Europe.
8. ………………. treaty signed on February 7,1992 created the European Union.

Answers:

1. Dr. Sun Yat-Sen
2. Peking
3. Chiang-Kai-Sheik
4. Central Treaty organisation
5. Versailles
6. 1955
7. Strasbourg
8. Maastricht

III. Choose the correct statement / statements

Question 1.
(i) In China (1898) the young emperor, under the influence of the educated
minority, initiated a series of reforms known as the 100 days of reforms.
(ii) The Kuomintang Party represented the interests of the workers and peasants.
(iii) Yuan Shih-Kai had lost prestige in the eyes of Nationalists, when he agreed to the demand of Japan to have economic control of Manchuria and Shantung.
(iv) Soviet Union refused to recognize the People’s Republic of China for more than two decades.
(a) (i) and (ii) are correct
(b) (ii) and (iii) are correct
(c) (i) and (iii) are correct
(d) (i) and (iv) are correct
Answer:
(c) (i) and (iii) are correct

Question 2.
(i) In 1948, the Soviets had established left wing government in the countries of Eastern Europe that had been liberated by the Soviet Army.
(ii) The chief objective of NATO was to preserve peace and security in the North Atlantic region.
(iii) The member countries of SEATO were committed to prevent democracy from gaining ground in the region.
(iv) Britain used the atomic bomb against Japan to convey its destructive capability to the USSR.
(a) (ii), (iii) and (iv) are correct
(b) (i) and (ii) are correct
(c) (iii) and (iv) are correct
(d) (i), (ii) and (iii) are correct
Answer:
(b) (i) and (ii) are correct

Question 3.
Assertion (A): America’s Marshall Plan was for reconstruction of the war¬. ravaged Europe.
Reason (R): The US conceived the Marshal Plan to bring the countries in the Western Europe under its influence.
(a) Both (A) and (R) are correct, but R is not the correct explanation of A
(b) Both (A)and (R) are wrong
(c) Both (A) and (R) are correct and R is the correct explanation of A
(d) (A) is wrong and (R) is correct.
Answer:
(c) Both (A) and (R) are correct and R is the correct explanation of A

IV. Match the following

Answer:
A. (ii)
B. (iii)
C. (iv)
D. (v)
E. (i)

V. Answer briefly

Question 1.
Write any three causes for the Chinese Revolution of 1911.
Answer:
Three causes of the Chinese Revolution of 1911 are

1. The government of Manchu dynasty began to disintegrate with the death of the Empress Dowager Cixi in 1908. The new emperor was two-years old and the provincial governors began to assert their independence. In October 1911 the local army mutinied and the revolt spread.
2. There were a few middle class leaders. Dr. Sun Yat-sen was one among them. He took part in the rising against the Manchus in 1895. The rising failed and Sun Yat-Sen was sent in the prison. But he continued to spread nationalist ideas.
3. Yuan Shih-Kai, who had earlier served as a minister in the Manchu administration, persuaded those responsible for the ascension of the young Emperor to prevant on him to abdicate.

Question 2.
Explain how in 1928 Kuomintang and Chiang-Kai Shek established Central Government in China.
Answer:
Chiang Kai-shek started conquering China. Starting from Canton, in 1928, he captured Peking and also removed all communists in the Kuomintang party. Thus, he established Central government in China.

Question 3.
Write a note on Mao’s Long March.
Answer:
Mao was an active leader who had gained full control of the Chinese Communist Party, by 1933. In 1934, he organised communist army of about 100,000 and set out on a long March. The marchers were continually harassed by Kuominatang forces, by local war lords and by unfriendly tribesmen of the 100,000 who set out, only 20,000 finally arrived in northern Shemi in late 1935, after crossing nearly 6000 miles. They were soon poined by other communist armies. By 1937, Mao had become the leader of over 10 million people. Mao’s Long March, as it is called so, has become legendary in the history of China.

Question 4.
What do you know of Baghdad Pact?
Answer:
In 1955, Turkey, Iraq, Great Britain, Iran and Pakistan signed a pact known as Baghdad pact. In 1958, when United States joined, then it was called as Central Treaty organization. The treaty was open to any Arab nation desiring peace and security in their region. It was dissolved in 1979.

Question 5.
What was the Marshall Plan?
Answer:
The Marshall Plan was an American initiative passed in 1948 to and Western Europe, in which the United States gave over $12 Billion in economic assistance to help rebuild Western European economies after the end of World War II. It operated for four years beginning in April 1948. The goals of the United States were to rebuild war-tom regions, modernise industry and improve European prosperity.

Question 6.
The Suez Canal crisis confirmed that Israel had been created to serve the cause of western interests-Elaborate.
Answer:
In 1956, Egypt invaded Suez Canal under Colonel Nasser and nationalized it. With the failure of diplomacy, Britain and France decided to use force. They bombed Egyptian air fields as well as Suez Canal area. However, United States and United Nations pressure, all the three invaders withdrew from Suez Canal.

Question 7.
Write a note on Third World Countries.
Answer:
The capitalist countries led by the US were politically designated as the First Worlds, while the communist states led by the Soviet Union came to be known as the Second World states, outside these two were called third World. During the Cold War, third World consisted of the developing world the former colonies of Africa, Asia, and Latin America. With the break up of the Soviet Union in 1991, and the process of globalisation, the term Third World has lost its relevance.

Question 8.
How was the Cuban missile crisis defused?
Answer:
In April 1961, on the island of Bay of Pigs, U.S bombed Cuban airfields and surrounded Cuba, with their warships. At the same time, USSR was secretly installing nuclear missiles in Cuba. Finally when Soviet President Khrushchev agreed to withdraw the missiles, the Cuban missile-crisis defused.

VI. Answer all the questions under each caption

Question 1.
Cold War

(a) Name the two military blocs that emerged in the Post-World War II.
Answer:
United States and the Soviet Union were the two military blocs that emerged in the post World War-II.

(b) Who coined the term “Cold War” and who used it first?
Answer:
The term Cold war was first coined by the English writer George Orwell in 1945 and it was used for the first time by Bernard Baruch, a multimillionaire from USA.

(c) What was the response of Soviet Russia to the formation of NATO?
Answer:
Warsaw Pact was the response of Soviet Russia to the formation of NATO.

(d) What was the context in which Warsaw Pact was dissolved?
Answer:
With the Break-up of USSR in 1991, the Warsaw Pact was dissolved.

Question 2.
Korean War

(a) Who was the President of North Korea during the Korean War?
Answer:
Kim II was the President of North Korea during the Korean War.

(b) Name the southern rival to the President of North Korea.
Answer:
Syngman Rhee

(c) How long did the Korean War last?
Answer:
The Korean War lasted three years

(d) What was the human cost of the War?
Answer:
The human cost was enormous, there were 500,000 western casualties and three times that number on the other side. Approximately two million Korean civilian died.

Question 3.
Non-Aligned Movement (NAM)

(a) When and where was the first conference on Non-Aligned Movement held?
Answer:
At Belgrade, in 1961, the first conference on NAM was held.

(b) Who were the prominent personalities present in the first conference?
Answer:
The prominent personalities present in the first conference were Tito (Yugoslavia), Nasser (Egypt), Nehru (India), Nikrumah (Ghana), Sukrano (Indonesia),.

(c) What were the objectives of NAM?
Answer:
Peaceful co-existence, commitment to peace and security.

(d) List out any two basic principles of Non-Alignment Movement enunciated in the Belgrade Conference.
Answer:

1. Non-Alignment with any of the two super powers (USA/USSR).
2. Fight all forms of colonialism and Imperialism.

VII. Answer in detail

Question 1.
Estimate the role of Mao Tse tung in making China a communist country.
Answer:

1. Mao was greatly influenced by the ideas of Max and Lenin. He wanted to make China a communist country. So, he became active in the political activities of Hunan from the year 1912.
2. After the death of Sun Yat-Sen in 1925, The Kuomintang was organised under the leadership of Chang Kai-Shek. Being an avowed critic of communists, Chiang removed all the important position holders in the Communist Party including Mao Tse Tung to weaken the party. However, the communists continued to influence the workers and peasants the Kuomintang represented the interests of landlords and capitalists.
3. Mao had understood that the Kuomintang grip on the towns was too strong. So, he started organising the peasantry. When the relationships between Kuomintang and Communist Party broke, a few hundred Communist-led by Mao retreated into the wild mountains on the border between the provinces of Kiangsi and Hunan. The Kuomintang could not penetrate the mountains.
4. Meanwhile, the campaign against the communists got distracted as Chiang Kai-Shek had to deal with the constant threat from Japan.
5. By 1933 Mao had gained full control of the Chinese Communist Party. In 1934, he set out on a long march with the help of about 100,000 communist army. He also got support of other communist armies.
6. By 1937, Mao had become the leader of over 10 million people. He organised workers and peasants councils in villages of Shensi and Kansu and finally got success in making China a communist country.

Question 2.
Attempt an essay on the Arab-lsraeii wars of 1967 and 1973.
Answer:

1. Before the creation of the State of Israel in 1948, all Arabs and their . descendants lived in the Palestine.
2. Ever since the formation, the Palestinian Liberation organisation (PLO). Israel came to be attacked by the Palestinian Guerrilla groups based in Syria, Lebanon and Jordan.
3. Israel resorted to violent military force .
4. In November 1966, an Israeli strike on the village of Al-Samu in the west bank of Jordan killed 18 people and wounded 54 people.
5. Israel’s air battle with Syria in April 1967 ended in the shooting down of six Syrian MIG fighter jets.
6. After air battle with Syria, when Arab States were mobilized by Nasser on June 5th Israel staged a sudden air strike that destroyed more than, 90% of Egypt’s air force on the tarmac.
7. Later, Egypt and Syria under Presidents Anwar Sadat and Hafez-al- Assad respectively concluded a secret agreement in January 1973 to bring their armies under one command.
8. When peace deals did not work out with Israel, Egypt and Syria launched a sudden and surprise attack on the Yom Kippur religious holiday on 6^th October 1973.
9. Though Israel suffered heavy casualities, it finally pushed back the Arab forces.
10. Due to U.N intervention, Israel was forced to return and Arabs gained nothing.
11. U.S succeeded in showing their control on their region and oil resource, led to U. S led war against Iraq in 1991.

Question 3.
Narrate the history of transformation of Council of Europe into an European Union.
Answer:
(i) After World War II, it was decided to integrate the states of western Europe. One of the chief objectives was to prevent further European wars by ending the rivalry between France and Germany. In May 1949, ten countries met in London and signed a form called Council of Europe

(ii) Since the Council of Europe had no real power, a proposal to set up two European organisations were made. Accordingly, the European Defence Community (EDC) and the European Coal and Steel Community (ECSC) were established. Six countries belonging to ECSC signed the treaty of Rome which established the European Economic Community (EEC) or the European Common Market, with headquarters at Brussels.

(iii) The EEC facilitated the elimination of barriers to the movement of goods and services, capital, and labour. It also prohibited public policies or private agreements that restricted market comptetion. Throughout the 1970s and 80s the EEC kept expanding its membership.

(iv) The single European Act came into force on July 1, 1987. It significantly expanded the EEC’s scope giving the meetings of the EPC a legal basis. It also called for more intensive coordination of foreign policy among member countries. According to the SEA each member was given multiple votes, depending on the countries population.

(v) The Maastricht (Netherlands) Treaty signed on February 7, 1992, created the European Union (EU). Today the European Union has 28 member states, and is functioning from its headquarters at Brussels, Belgium.

VIII. Activity

Question 1.
Divide the class into two groups. Let one group act as supporters of USA and the other group act as supporters of Soviet Union, Organise a debate.
Answer:
One group of students act as the supports of USA and the other group act as supporters of Soviet Union on their role in the cold war era.
(Students can have debate based on the following aspects)

During the time of cold war, the two super powers that emerged was USA and USSR.

Strengths of USA:

1. Strongest navy both the Pacific and Atlantic.
2. Continued and strong economic position that the USA held in the beginning till the end.
3. Foreign policy of the USA. The actions of USA during the cold war era, very powerful and could guarantee others the strong power of the nation is to prevent communism spreading elsewhere.
4. The country was able to generate the vast amount of wealth necessary to sustain the investment in weapons, technology and other operations.
5. USA was also technologically powerful in target finding, tracking, sensors etc.
6. The Truman’s doctrine was used throughout the war time. The doctrine helped USA to negotiate with other states to adopt capitalism.

Strengths of USSR:

1. Strongest land based military, especially tanks.
2. USSR developed air defense equipment and networks.
3. Spread of Communism joined together backed USSR.
4. As against NATO, USSR also formed military block, the Warsaw pact.
5. With Western European countries USSR facilitated trade relations.
6. Highly strengthened space exploration.

In the end of cold war, the Soviet Union fell, and the Communism expired.

Question 2.
Involving the entire class, an album may be prepared with pictures relating to Korean, Arab-lsraeli and Vietnam Wars to highlight the human sufferings in terms of death and devastation.
Answer:
Students should go to the search engine in google and type “The War’s impact on the Korean peninsula and trace the article of the journal of America – East Asia Relations” for a detailed Report.

Korean War: To give a sample answer: According to a U.S. Department of state publication, the number of killed, wounded and missing from the Armed forces of the Republic of Korea exceeded 4,00.000. From the U.S. side, 1,42,000. In addition, the heavy toll in death and injuries to the civilian population as well as wide property damage.

Arab-Israel War: Students should trace the answer from the google search engine as: The U.N. Report on Israel’s Gaza War.

To give a sample answer: From the 183 page report of the U.N. report, it is very clear that many civilians died. More than 6,000 Israeli airstrikes, 14,500 tank shells and 35,000 artillery shells led to the destruction of about 18,000 dwellings in Gaza. Nearly 1,462 Palestinian civilians, 299 women and 551 children were killed (According to U.N. Investigation). In Israel six civilians and 67 soldiers were killed.

Vietnam War: Students should trace the answer in the google search engine as “The War’s effect on the Vietnamese Land and People” for a detailed report.

To give a sample answer: About 58,000 American soldiers were killed and another 3,04,000 were wounded. Since most of the fighting took place in Vietnam, an estimated 4 million Vietnamese were killed on both sides including as many as 1 -3 million civilians. Many Vietnamese in country side turned into homeless refuges. Many forms and forests were destroyed.

Along with the detailed report, students should collect pictures showing Korea, Arab-Israel and Vietnam War, highlighting human sufferings. Students should click to google search engine and go to → Images → then type Korean War pictures / Arab Israel War pictures / Vietnam War pictures, download it take a print out of its and paste it in a A4 sheet paper or an a chart paper neatly and create an album.

Timeline:

Samacheer Kalvi 10th Social Science The World after World War II Additional Important Questions and Answers

I. Choose the correct answer

Question 1.
The emergence of ……………. and ……………. as super powers resulted in the division of the World into two block after World War II.
(a) Japan, USA
(b) USA, USSR
(c) China, Japan
(d) USA, Germany
Answer:
(b) USA, USSR

Question 2.
Dr.Sun yat-sen was born in a poor family near ………
(a) Canton
(b) France
(c) Spain
Answer:
(a) Canton

Question 3
……………. was called the father of modern China.
(a) Chiang-Kai-Shek
(b) Yuan-Shi-Kai
(c) Mao-Tse-Tung
(d) Dr. Sun Yat-Sen
Answer:
(d) Dr. Sun Yat-Sen

Question 4.
Mao was born in ……… in South – East China.
(a) Cambodia
(b) Vietnam
(c) Hunan
Answer:
(c) Hunan

Question 5.
Yuan-Shi-Kai died in the year …………….
(a) 1912
(b) 1913
(c) 1915
(d) 1916
Answer:
(d) 1916

Question 6.
Which of the following is not a part of Indo – China?
(a) Cambodia
(b) China
(c) Vietnam
Answer:
(b) China

Question 7.
The Historical Long March set out in China in …………….
(a) 1935
(b) 1937
(c) 1934
(d) 1936
Answer:
(c) 1934

Question 8.
In which of the following was indentured Vietnamese labour widely used?
(a) Rice cultivation
(b) Rubber plantation
(c) Industry
Answer:
(b) Rubber plantation

Question 9.
……………. was the leader of the people’s Republic of China.
(a) Marshall
(b) Truman
(c) Mao-Tse-Tung
(d) Chiang-Kai-shek
Answer:
(c) Mao-Tse-Tung

Question 10.
Ho Chi Minh means ………
(a) He, Who enlightens
(b) Enlightenment
(c) The Enlightened one
Answer:
(a) He, Who enlightens

Question 11.
The Idea of European self-help programme financed by the United States was called as …………….
(a) NATO
(b) SEATO
(c) ECA
(d) Marshall plan
Answer:
(d) Marshall plan

Question 12.
EURATOM was established by the ………
(a) Treaty of Nanking
(b) Treaty of Rome
(c) Treaty of London
Answer:
(b) Treaty of Rome

Question 13.
The term ‘cold war’ was first coined by the English writer …………….
(a) Shakespeare
(b) George Orwell
(c) William Dexter
(d) Peter Alphonse
Answer:
(b) George Orwell

Question 14.
As a part of Marshall plan financing, European nations received nearly ……………. billion in aid.
(a) $ 12
(b) $ 11
(c) $ 15
(d) $ 13
Answer:
(d) $ 13

Question 15.
Greece and Turkey joined NATO in the year …………….
(a) 1945
(b) 1947
(c) 1952
(d) 1955
Answer:
(c) 1952

Question 16.
……………. was otherwise called as pact.
(a) NATO
(b) CENTO
(c) SEATO
(d) EC SC
Answer:
(d) EC SC

Question 17
……………. are included as member countries in NATO.
(a) Canada, Belgium
(b) U.K., Portugal
(c) Both (a) and (b)
(d) None of the above
Answer:
(c) Both (a) and (b)

Question 18.
NATO had ……………. members by the year 2017.
(a) 30
(b) 51
(c) 29
(d) 24
Answer:
(c) 29

Question 19.
In December 1954, a conference of eight European nations took place in Moscow. This was called as …………….
(a) Warsaw pact
(b) Counter to NATO
(c) SEATO
(d) Both (a) and (b)
Answer:
(d) Both (a) and (b)

Question 20.
The headquarters of the Warsaw pact was …………….
(a) Belgium
(b) Poland
(c) Moscow
(d) Romania
Answer:
(c) Moscow

Question 21.
The Korea was partitioned into North and South Korea in the year …………….
(a) 1944
(b) 1945
(c) 1946
(d) 1947
Answer:
(b) 1945

Question 22.
With the collapse of the ……………. the idea of non-alignment lost relevance.
(a) Berlin
(b) CIA
(c) ECA
(d) Soviet Union
Answer:
(d) Soviet Union

Question 23.
The NAM held its first conference at ……………. in 1961.
(a) Bandung
(b) Belgrade
(c) Thailand
(d) Philippine
Answer:
(b) Belgrade

Question 24.
The World Zionist Organisation was founded in the year …………….
(a) 1857
(b) 1887
(c) 1897
(d) 1867
Answer:
(c) 1897

Question 25.
Castro nationalised the U.S. owned ……………. companies.
(a) cotton
(b) sugar
(c) oil
(d) petrol
Answer:
(b) sugar

Question 26.
The Cuban Missile crisis was defused by ……………. as the agreed to withdraw the missiles.
(a) Khrushchev
(b) Fidel Castro
(c) Leumi
(d) Stem Gang
Answer:
(a) Khrushchev

Question 27.
In the Arab World, it is treated as the ……………. when large number of Arabs become refugees.
(a) Catastrophe
(b) Nakbah
(c) Negev and (b)
(d) Both (a) and (b)
Answer:
(d) Both (a) and (b)

Question 28.
For resolving the Suez Canal Crisis, ……………. from Indian played a crucial role.
(a) Gandhi
(b) Nehru
(c) Bose
(d) Tilak
Answer:
(b) Nehru

Question 29.
Arab-lsrael war took place in the years …………….
(a) 1967,69
(b) 1969,74
(c) 1967,73
(d) 1972,73
Answer:
(c) 1967,73

Question 30.
……………. became the first president of the state of Palestine in 1989.
(a) Anwar Sadat
(b) Yasser Arafat
(c) Nasser Arafat
(d) Nasser Hussain
Answer:
(b) Yasser Arafat

Question 31.
By the end of second world war, ……………. controlled the northern half of Vietnam.
(a) Vietminh
(b) Ho-Chi-Minh
(c) Ngo Dinh Diem
(d) None
Answer:
(a) Vietminh

Question 32.
……………. controlled the southern half of the Vietnam.
(a) Viet Minh
(b) Bao Dai
(c) Ngo Dinh Diam
(d) None
Answer:
(b) Bao Dai

Question 33.
The North and the South Vietnam were formally united as one country in …………….
(a) 1973
(b) 1976
(c) 1975
(d) 1974
Answer:
(b) 1976

Question 34.
In May 1949, ten countries met in ……………. and signed to form a council of Europe.
(a) Japan
(b) Syria
(c) London
(d) France
Answer:
(c) London

Question 35.
To prevent further European War ……………. was founded.
(a) Council of Europe
(b) Council of Trent
(c) ECSC
(d) EU
Answer:
(a) Council of Europe

Question 36.
……………. did not join the EEC, when it was formed.
(a) U.K
(b) U.S.A
(c) USSR
(d) Italy
Answer:
(a) U.K

Question 37.
Britain, voted to exit the EU in the year …………….
(a) 2015
(b) 2014
(c) 2017
(d) 2019
Answer:
(c) 2017

Question 38.
West Berlin was supported by …………….
(a) USA
(b) UK
(c) USSR
(d) Germany
Answer:
(a) USA

Question 39.
East Berlin was supported by …………….
(a) USA
(b) UK
(c) USSR
(d) Germany
Answer:
(c) USSR

Question 40.
Germany was officially united on …………….
(a) 1987
(b) 1989
(c) 1990
(d) 2003
Answer:
(c) 1990

Question 41.
in 1985, ……………. became the head of the USSR.
(a) Mikhai Gorbachev
(b) Reagen
(c) Stalin
(d) Kohl
Answer:
(a) Mikhai Gorbachev

Question 42.
The Chernobyl disaster took place in the year …………….
(a) 1987
(b) 1984
(c) 1986
(d) 2006
Answer:
(c) 1986

Question 43.
Gorbachev announced his resignation on …………….
(a) 21st November
(b) 25th December
(c) 2nd October
(d) 15th August
Answer:
(b) 25th December

Question 44.
USSR dissolved formally In the year …………….
(a) 31st Dec. 1990
(b) 30th Dec. 1991
(c) 31st Dec. 1991
(d) 28,h Feb. 1991
Answer:
(c) 31st Dec. 1991

Question 45.
……………. was an ally of Gorbachev.
(a) Yeltsin
(b) Brezhnev
(c) Khrushchev
(d) None
Answer:
(a) Yeltsin

II. Fill in the blanks

1. ………………… and ………………… were the Superpowers after the World War II.
2. The cold war period ended with the fall of …………………
3. Empress Dowager died in ………………… led to the disintegration of the Manchu dynasty.
4. Kuomintang party of China was otherwise called as ………………… party.
5. ………………… was the ultimate aim of Dr. Sun Yat-sen’s party.
6. The Chinese revolution broke out in the year …………………
7. The first director of the Whampoa Military academy was …………………
8. The campaign against the communists led by Chiang-Kai-Shek was distracted by ………………… and warlords.
9. By ………………… Mao became the leader of the Chinese people.
10. Over ………………… delegates from various countries attended the people’s political consultative conference.
11. When Japanese surrendered in 1945, the Japanese areas were occupied by the …………………
12. By the year …………………, communist control has been established over most parts of China.
13. The two mighty communist powers in the world were ………………… and …………………
14. The term cold war was first coined by …………………
15. ………………… nations became a part of Marshall’s plan of self-help programme.
16. The Marshall plan funding ended in …………………
17. ………………… was created to resist Soviet aggression in Europe.
18. NATO means …………………
19. NATO was formed in the year …………………
20. The members of NATO agreed that, any armed attack on any one of them would be considered attack on …………………
21. For the collective security of the South-east Asia, ………………… was formed in 1954.
22. Member of SEATO were committed to prevent …………………
23. SEATO was formed in 1954, after signing of the …………………
24. ………………… was formed by Soviet Union as a counter to NATO.
25. ………………… European nations attended the Warsaw pact in December 1954.
26. The treaty on Warsaw pact was concluded on …………………
27. The Warsaw pact was dissolved in …………………
28. The Warsaw pact dissolved because of the break-up of …………………
29. The Baghdad pact was otherwise called as …………………
30. Turkey, Iran, Iraq, Pakistan and Great Britain signed a treaty in 1955, known as …………………
31. When U.S.A joined the Baghdad pact, it was called by name …………………
32. USA joined the Baghdad pact in the year …………………
33. CENTO was dissolved in the year …………………
34. Korea was partitioned as North Korea and South Korea in the year …………………
35. The president of North Korea was …………………
36. The party of Kim II was called as …………………
37. The president of the South Korea was …………………
38. The party of Syngman Rhee was …………………
39. Korean War lasted for ………………… years.
40. NAM refers to the …………………
41. NAM was signed in ………………… at the ………………… conference.
42. Bandung is a city in …………………
43. With the collapse of ………………… the idea of NAM lost importance.
44. CIA is a Central Intelligence Agency of …………………
45. The Act of ………………… in Cuba, threatened American economic interests.
46. USA bombed Cuban ………………… with the aim of overthrowing Castro’s regime.
47. ………………… was the president of USSR, when the Cuban Missile crisis took place.
48. Cuba was helped by …………………
49. When USSR remove missile from Cuba, USA had to agree to remove missile from ………………… and …………………
50. ………………… was a Zionist Terrorist Organisation.
51. The Zionist Para-military organization was called as …………………
52. The World Zionist organization was founded in the year …………………
53. Jews living outside their ancient home scattered around North America and Europe was called as …………………
54. ………………… Nationalised Suez Canal.
55. India represented by ………………… played a crucial role in resolving the crisis.
56. The Arab-lsraeli War took place in the years ………………… and …………………
57. PLO refers to …………………
58. PLO was formed in …………………
59. ………………… was the prominent leader of Palestine.
60. By the end of the Second World War, ………………… Controlled the northern half of Vietnam.
61. South Vietnam was ruled by …………………
62. America supported troops of ………………… Vietnam.
63. The city of ………………… was renamed as Ho-Chi-Minh city.
64. To create a United Europe to resist any threat from Soviet Russia, ………………… was formed.
65. European Economic Community was otherwise called as …………………
66. SEA refers to …………………
67. According to the SEA, each member was given ………………… votes.
68. The ………………… Treaty created the European Union.
69. Maastricht is in …………………
70. EU was created on Maastricht treaty signed on …………………
71. The headquarters of the EU is at …………………
72. Brussels is at …………………
73. ………………… Germany was prosperous.
74. ………………… Germany was suffering from lack of democracy and freedom.
75. Germany was officially reunited on …………………
76. Glasnost means …………………
77. Perestroika means …………………
78. ………………… was introduced by Gorbachev to restructure Soviet economic and political system.
79. After Gorbachev, power fell into the hands of …………………
80. For ………………… days, Soviet Union, continued to exist only in name.
81. Soviet Union dissolved formally on 31st December …………………
82. USSR split into ………………… countries.
83. ………………… was the president of the newly independent Russian State.
84. U.S.A. troops used ………………… weapons in their war against Vietnam.
85. Napalm and Agent Orange are the names of incendiary …………………

Answers:

1. USA and USSR
2. Berlin Wall
3. 1908
4. National People’s Party
5. Socialism
6. 1911
7. Chiang-Kai-Shek
8. Japan
9. 1937
10. 650
11. Kuomintang
12. 1948
13. Soviet Union, People’s Republic of China
14. George Orwell
15. Sixty
16. 1951
17. NATO
18. North Atlantic Treaty Organisation
19. 1949
20. NATO
21. SEATO
22. Communism
23. Manila Pact
24. Warsaw Pact
25. 8 (eight)
26. May 14, 1955
27. 1991
28. USSR
29. Central Treaty Organisation
30. Baghdad Pact
31. Central Treaty Organisation
32. 1958
33. 1979
34. 1945
35. Kim II
36. People’s Republic of Korea
37. Syngman Rhee
38. The Republic of Korea
39. three
40. Non-Aligned Movement
41. 1955, Bandung
42. Indonesia
43. Soviet Union
44. America
45. Castro
46. Airfields
47. Khrushchev
48. USSR
49. Turkey, Italy
50. Stem Gang
51. Irgun Zvai Leumi
52. 1897
53. Diaspora
54. Colonel Nasser
55. Nehru
56. 1967, 1973
57. Palestine Liberation Organisation
58. 1948
59. Yasser Arafat
60. Viet Minh
61. Ngo Dinh Diem
62. South
63. Saigon
64. Council of Europe
65. European Common Market
66. Single European Act
67. multiple
68. Maastricht
69. Netherlands
70. Feb 7, 1992
71. Brussels
72. Belgium
73. West Berlin’s
74. East Berlin
75. 3rd October 1990
76. openness
77. restructuring
78. Perestroika
79. Boris Yeltsin
80. Six 81.1991
81. 15
82. Boris Yeltsin
83. Bacteriological
84. bombs

III. Choose the correct statement / statements

Question 1.
(i) The cold war period ended with the fall of Berlin Wall
(ii) Mao concentrated mainly on organizing the peasantry.
(iii) In 1937, the communist army of about 100,000 set out on the Long march.
(iv) Marshall plan funded nearly $ 15 billion.
(a) (ii and (ii) are correct
(b) (i) and (iii) are correct
(c) (ii and (iv) are correct
(d) (iii) and (iv) are correct.
Answer:
(a) (ii and (ii) are correct

Question 2.
(i) The USSR was much concerned about the destruction caused by the Second World War.
(ii) The South East Asia Treaty organization was organised for the collective security of countries in South East Asia.
(iii) The Communist States led by the Soviet Union came to be known First World Countries.
(iv) The Capitalist countries led by the U.S.A. were politically designated as Second World Countries.
(a) (i) and (ii) are correct
(b) (i), (iii), (iv) are wrong
(c) (i) and (iv) are correct
(d) (ii) and (iii) are correct.
Answer:
(b) (i), (iii), (iv) are wrong

Question 3.
(i) NAM refers to the Non-Aligned Movement.
(ii) The Single European Act of the EU as called as SEA.
(iii) Anwar Sadat was the president of the Palestine in 1989.
(iv) The fighters of South Vietnam were trained in guerrilla warfare.
(a) (i) and (ii) are correct
(b) (i), (iii), (iv) are wrong
(c) (i) and (iv) are correct
(d) (ii) and (iii) are correct.
Answer:
(a) (i) and (ii) are correct

Question 4.
(i) The Third World principally consist of the developing World.
(ii) With the breakup of the Soviet Union in 1991, and the process of globalization, the term has lost its relevance.
(iii) The former colonies of Asia, Africa, and Latin America were called as Third World Countries.
(iv) The division of Germany into West and East led to glaring differences in living standards.
(a) (i) and (ii) are correct
(b) (i), (ii), (iii) are correct
(c) (i) and (iii) are correct
(d) All the four are correct.
Answer:
(d) All the four are correct.

Question 5.
(i) Yeltsin worked as a Mayor of Moscow.
(ii) Yeltsin was returned to power with overwhelming support of a Moscow in 1899.
(iii) For twelve days, the Soviet Union continued to exist only in name.
(iv) On 28th February 1991, USSR was formally dissolved.
(a) (i) and (ii) are correct
(b) (i), (ii), (iii) are correct
(c) (i) and (iii) are correct
(d) All the four are correct.
Answer:
(a) (i) and (ii) are correct

Question 6.
(i) CENTO was otherwise called as Manila pact.
(ii) As a counter to SEATO, NATO was formed.
(iii) The Korean war helped to bring down the intensity of the Cold war.
(iv) The EEC eliminated barriers to the movement of goods, Capital and labour.
(a) (i) and (ii) are correct
(b) (i), (ii), (iii) are wrong
(c) (i) and (iv) are correct
(d) All the four are correct.
Answer:
(b) (i), (ii), (iii) are wrong

Question 7.
(i) The Berlin Wall was just a physical barrier.
(ii) Berlin Wall divided East Germany and West Germany.
(iii) USA supported East Berlin.
(iv) USSR supported West Berlin.
(a) (i) and (ii) are correct
(b) (i), (ii), (iii) are wrong
(c) (i) and (iv) are correct
(d) All the four are wrong.
Answer:
(a) (i) and (ii) are correct

IV. Assertion and Reason

Question 1.
Assertion (A): Yuan Shih-Kai of China lost prestige in his country.
Reason (R): He agreed to the demand of Japan to have economic control of Manchuria and Shantung.
(a) Both (A) and (R) are correct, R is not the correct explanation of A
(b) Both (A) and (R) are wrong
(c) Both (A) and (R) are correct, and R is the correct explanation of A
(d) (A) is wrong and (R) is correct.
Answer:
(c) Both (A) and (R) are correct, and R is the correct explanation of A

Question 2.
Assertion (A): The rivalry that developed after World War 11 is referred to as “Cold War”.
Reason (R): This war did not take recourse to weapons.
(a) Both (A) and (R) are correct, R is not the correct explanation of A
(b) Both (A) and (R) are wrong
(c) Both (A) and (R) are correct, and R is the correct explanation of A
(d) (A) is wrong and (R) is correct.
Answer:
(c) Both (A) and (R) are correct, and R is the correct explanation of A

Question 3.
Assertion (A): There was High military expenditure on both sides of USA and USSR.
Reason (R): Soviet Union tested the nuclear bomb and America used the nuclear bomb against Japan.
(a) Both (A) and (R) are correct, R is not the correct explanation of A
(b) Both (A) and (R) are wrong
(c) Both (A) and (R) are correct, and R is the correct explanation of A
(d) (A) is wrong and (R) is correct.
Answer:
(c) Both (A) and (R) are correct, and R is the correct explanation of A

Question 4.
Assertion (A): The U.S. and its European allies formed the NATO to wage war against Vietnam.
Reason (R): As a counter to the NATO, Soviet Union organised the Warsaw pact.
(a) Both (A) and (R) are correct, R is not the correct explanation of A
(b) Both (A) and (R.) are wrong
(c) Both (A) and (R) are correct and R is the correct explanation of A
(d) (A) is wrong and (R) is correct.
Answer:
(d) (A) is wrong and (R) is correct.

Question 5.
Assertion (A): A small country had succeeded in winning Independence and the greatest power of the World-The country Vietnam.
Reason (R): The help given to Vietnam by the Socialist Countries, the political support given by Asia and Africa is evident.
(a) Both (A) and (R) are correct, R is not the correct explanation of A
(b) Both (A) and (R) are wrong
(c) Both (A) and (R) are correct and R is the correct explanation of A
(d) (A) is wrong and (R) is correct.
Answer:
(c) Both (A) and (R) are correct and R is the correct explanation of A

Question 6.
Assertion (A): Sun Yat-sen sent Chiang Kai-shek to Moscow, in Russia. The Russians in turn sent Michael Borodin to China.
Reason {R): Chiang Kai-shek started conquering China from Canton.
(a) Both (A) and (R) are correct, R is not the correct explanation of A
(b) Both (A) and (R) are wrong
(c) Both (A) and (R) are correct and R is the correct explanation of A
(d) (A) is wrong and (R) is correct.
Answer:
(a) Both (A) and (R) are correct, R is not the correct explanation of A

Question 7.
Assertion (A): U.S.A. supported Diem government in South Vietnam. Reason (R): U.S. wanted to establish a strong government in South Vietnam.
(a) Both (A) and (R) are correct, R is not the correct explanation of A
(b) Both (A) and (R) are wrong
(c) Both (A) and (R) are correct and R is the correct explanation of A
(d) (A) is wrong and (R) is correct.
Answer:
(c) Both (A) and (R) are correct and R is the correct explanation of A

V. Match the following

Question 1.
Match the Column I with Column II.

Answer:
A. (v)
B. (iii)
C. (ii)
D. (i)
E. (vi)

Question 2.
Match the Column I with Column II.

Answer:
A. (iv)
B. (iii)
C. (i)
D. (ii)
E. (vi)

VI. Answer briefly

Question 1.
Describe about Zionist movement.
Answer:
(i) In Palestine, the ancient home of Jews, only a few thousand Jews were living in 1900.
(ii) Some 15 million were scattered around Europe and North America.
(iii) These Jews had been subjected to systematic persecution for centuries.
(iv) But in the late nineteenth century, the persecution in Russia (Where two-thirds of the world’s jews lived), France and Germany was intense.
(v) Some Jews emigrated to Palestine, while many more went to the United States and Britain.
(vi) In 1896, Thodore Herzel, a Viennese journalist, published a pamphlet called the Jewish state in which he called for the creation of a Jewish national home. In 1897 the world zionist organisation was founded.

Question 2.
What was Truman’s policy?
Answer:
Truman, the president of USA announced a policy of containment of communism. This implies U.S. would support those countries which were threatened by USSR to spread communism.

Question 3.
Mention the initial member countries of the EU.
Answer:

1. Belgium
2. France
3. Italy
4. Luxemburg
5. Netherlands
6. West Germany

Question 4.
What is meant by SEA?
Answer:
SEA refers to the single European Act which came into force on July 1,1987. According to the SEA, each member was given multiple votes depending on the country’s population. Its main aim is establishing a single market.

Question 5.
Name the organs of the EU.
Answer:

1. European parliament
2. Council of the European Union
3. European commission
4. Court of Justice
5. Court of Auditors

Question 6.
Write a note on European Union.
Answer:
On February 7, 1992, the Maastricht Treaty that signed in Netherlands created the European Union. All the member countries of the EU will use common currency Euro, a single market and common Act. EU at present has 28 members with head quarters at Brussels, Belgium.

Question 7.
How was the European union formed?
Answer:
According to the Merger Treaty of 1967, the three communities namely the European coal and steel community, the European Economic community and the European Atomic Energy community were merged together to form the European union.

VII. Answer all the questions under each caption

Question 1.
People’s Republic of China

(a) Who was the leader of the People’s Republic of China?
Answer:
Mao Tse-Tung was the leader of the People’s Republic of China.

(b) Name the two mighty Communist powers of the world?
Answer:
The Soviet-Union and the people’s Republic of China.

(c) Who did not recognise People’s Republic of China and for how long?
Answer:
The UNO refused to recognise people’s Republic of China for more than twenty years.

(d) How did the government of Taiwan got recognition?
Answer:
The government of Chiang Kai-shek in Taiwan was given recognition ‘ due to the pressure from USA.

Question 2.
Achievements of EU

(a) What is the symbol of the Euro?
Answer:
The symbol of the Euro is €.

(b) What did the Euro eliminate?
Answer:
The Euro eliminated foreign exchange hurdles encountered by companies doing business across European border.

(c) How many members are there in the EU at present?
Answer:
At present, there are 28 members in the EU.

(d) Who allocates funds to European research projects?
Answer:
The European Research council.

Question 3.
Disintegration of The Soviet Union.

(a) Who became the head of USSR in 1985?
Answer:
Mikhail Gorbachev became the head of the USSR in 1985.

(b) What is meant by “thaw”?
Answer:
The “Thaw” refers to the period from the early 1950’s and 1960’s when repression and censorship in the Soviet Union was relaxed and millions of political prisioners were released. It was the period of Khrushchev’s reign.

(c) What is meant by Glasnost?
Answer:
Glasnost means openness. It was the policy of more transperancy and openness in the government policy of former Soviet Russia introduced by Mikhail Gorbachev.

(d) What is meant by Perestroika?
Answer:
Perestroika means restructuring. It refers to the programme introduced by Mikhail Gorbhachev to restructure Soviet economic and political system.

Question 4.
Berlin Wall

(a) Who constructed a wall which virtually cut off West Berlin and East Berlin? and when?
Answer:
East German began to construct a wall in 1961 which virtually cut off West Berlin and East Berlin.

(b) How was it guarded?
Answer:
It was guarded with watchtowers and other lethal impediments to stop people from the east.

(c) What does the Berlin wall symbolise?
Answer:
It was symbolic boundary between Communism and Capitalism.

(d) What happened with the fall of the Berlin wall?
Answer:
With the fall of the Berlin wall , followed by the collapse of the Soviet Union, the cold war came to an end.

VIII. Answer in detail

Question 1.
Write a brief account of the life and achievements of Ho Chi Minh.
Answer:
He was born in a small town in Central Vietnam. He studied in French school that produced great leaders. After his studies he worked on a French liner operating between Saigon and Marseilles. He was greatly inspired by European communist parties, became member of commintem and was instrumental in bringing together competing nationalists groups to form the Vietnamese communist party in 1930. It was later renamed the Indo-Chinese communist party. After spending 30 years abroad in Europe, China Thailand, he returned to Vietnam in 1941. He became President of the Vietnam Democratic Republic in 1943.

After the split of Vietnam, he and the communists took control of North Vietnam. With the help of his government, National Liberation Front in the south fought for unification of the country. He fought hard to maintain the autonomy of Vietnam and till the end proved true to his name. Ho Chi Minh meaning He, Who Enlightens.

Question 2.
Illustrate the cold war developments in case of the Vietnam war. Narrate how North and South Vietnam unified as Independent Nation.
Solution:

1. By 1945, the end of the second world war, Viet Minh controlled the northern half of Vietnam, led by Ho-chi- Minh.
2. Viet Minh and french reached an agreement by which North Vietnam would be a free state.
3. While French was helped by America, Viet Minh was helped by the new Chinese communist government.
4. War broke out between them. Eventually , France troops were defeated.
5. The Geneva conference that met on Korea and Indo China in 1954, decided that of Laos. Combodia and Vietnam. The independent states would be Laos and Cambodia. Vietnam, temporarily divided.
6. While North Vietnam controlled by Viet Minh with leader Ho-Chi-Minh and south Vietnam would be under the leadership of Bao Dai.
7. At the same time, South Vietnam was ruled by Ngo Dinh Diem.
8. When U.S wanted to establish a strong Non-communist government in South Vietnam. In 1965, marines landed on Danang naval base and namely 2,10,000 traps in the country, j (ix) The U.S bombed both North and South.
9. The fighters of North Vietnam trained in Guerrilla warfare sustained.
10. America suffered heavy casualties , vast devastated and many were killed.
11. The youth rebelled against the horrors of the war.
12. The protest against the war spread all over the world.
13. By 1975, the armies of the North and the only one party of South Vietnam called National Liberation front of South Vietnam attacked America.
14. By 30th April 1975, all the American troops had withdrawn and capital of South Vietnam Saigon was liberated.
15. North Vietnam and South Vietnam formally united as one country in 1976.
16. The city of Saigon was renamed as the Ho-Chi-Minh city .
17. Thus, the emergence of Vietnam as a united and Independent nation was an historic event.

Question 3.
Explain the breakup of the Soviet Union.
Answer:

1. In the middle of 1980’s Soviet Union economy was suffering.
2. In 1985, Mikhail Gorbachev took over as the president of USSR.
3. Gorbachev spoke about the need for openness (Glasnost) and Perestroika (restructuring).
4. But his ideas of reform did not work out for him because, to compete with U.S, USSR need to allocate more funds to the military.
5. The economic stagnation of the Soviet Union aggrevated tension and promoted nationalist feelings.
6. In the year 1988, Mass protest broke out in Armenia and in the Baltic states.
7. Gorbachev made attempts to stabilize his position by relying on conservative forces in 1989, 1991.
8. But the massive miner’s strike interrupted. The series of worker’s strike under mined the communist regimes first in Poland, then in Hungary.
9. The fall of Berlin wall in Germany, encouraged people to be united.
10. Gorbachev made a last attempt to take a hard line against miner’s strike and huge demonstrations in Moscow in 1991.
11. In response, the conservative forces in his government used troops in Moscow and held Gorbachev under house arrest.
12. Power fell into the hands of Boris Yeltsin.
13. In November 1991, eleven republics announced that they would establish a common wealth of independent states.
14. On 25th Dec 1991 , Gorbachev resigned.
15. For six days, the Soviet Union continued to remain only in name and at midnight on 31st December 1991 it was formally dissolved.
16. The USSR was no more.

Students can Download Samacheer Kalvi 10th English Model Question Paper 3 Pdf, Samacheer Kalvi 10th English Model Question Papers helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams.

Tamil Nadu Samacheer Kalvi 10th English Model Question Paper 3

General Instructions:

1. The question paper comprises of four parts.
2. You are to attempt all the sections in each part. An internal choice of questions is provided wherever applicable.
3. All questions of Part I, II, III and IV are to be attempted separately.
4. Question numbers I to 14 in Part I are Multiple Choice Questions of one mark each. These are to be answered by writing the correct answer along with the corresponding – option code.
5. Part II has got four sections. The questions are of two marks each. Question numbers 15 to 18 in Section I and Question numbers 19 to 22 in Section II are to be answered in about one or two sentences each. Question numbers 23 to 28 in Section III and IV are to be answered as directed.
6. Question numbers 29 to 45 in Part III are of five marks each and have been divided in five sections. These are to be answered as directed.
7.  Question numbers 46 and 47 in Part IV are of eight marks each. Question number 47 has four questions of two marks each. These are to be answered as directed.

Time: 2.30 Hours
Maximum Marks: 100

Part – I

Answer all the questions. [14 x 1= 14]
Choose the most suitable answer and write the code with the corresponding answer.
Choose the appropriate synonyms for the italicised words.

Question 1.
He saw his older brother devour his first catch.
(a) consume
(b) devein
(c) divide
(d) smell
Answer:
(a) consume

Question 2.
A half-dozen policemen emerged out of the darkness.
(a) charged
(b) exit
(c) appeared
(d) jumped
Answer:
(c) appeared

Question 3.
Harvest was over.
(a) crop
(b) crab
(c) craze
(d) pests
Answer:
(a) crop

Choose the appropriate antonym for the italicised words.

Question 4.
In fact, I’d say it was easier for us to collaborate and work together.
(a) difficult
(b) calmer
(c) tranquility
(d) quicker
Answer:
(a) difficult

Question 5.
Your entire energy management can be taken care by automating.
(a) complete
(b) partial
(c) perfect
(d) whole
Answer:
(b) partial

Question 6.
You will persuade him to come.
(a) urge
(b) dissuade
(c) disembark
(d) distract
Answer:
(b) dissuade

Question 7.
Choose the correct plural form of ‘goose‘.
(a) goose
(b) gooses
(c) goosies
(d) geese
Answer:
(d) geese

Question 8.
Form a derivative by adding the right suffix to the word- ‘lonely‘.
(a) ment
(b) al
(c) ity
(d) ness
Answer:
(d) ness

Question 9.
Choose the correct expansion of the abbreviation IPKF is ………………………
(a) Institute of Peace Keeping Federation
(b) Indian Piece Keeping Force
(c) Intelligent Peace Keeping Force
(d) Indian Peace Keeping Federation
Answer:
(b) Indian Piece Keeping Force

Question 10.
Complete the following sentence with the most appropriate phrasal verb given below:
Shelton …………………………………. his jacket and went out.
(a) put on
(b) put down
(c) put off
(d) put aside
Answer:
(c) put off

Question 11.
Choose the suitable option to pair it with the word ‘bow‘ to form a compound word,
(a) tail
(b) high
(c) rain
(d) hand
Answer:
(c) rain

Question 12.
Fill in the blank with the most appropriate preposition given below:
The crew started their voyage on ………………… 10 September 2017.
(a) from
(b) at
(c) on
(d) by
Answer:
(c) on

Question 13.
Complete the following sentence using the most appropriate tense form of the verb given below:
When we ………….. the Tasman Sea, we witnessed the brilliant Southern Lights from sea.
(a) will cross
(b) were crossing
(c) is cross
(d) will be crossed
Answer:
(b) were crossing

Question 14.
Choose the most appropriate linker from the given four alternatives.
Raghu added salt ……………. sugar to the milk.
(a) else
(b) so
(c) instead of
(d) but
Answer:
(c) instead of

Part – II [10 x 2 = 20]
Section – I

Answer any THREE of the following questions in a sentence or two. [3 x 2 = 6]

Question 15.
Why did Holmes want Smith to treat him?
Answer:
Holmes believed Mr. Smith, a plantation man, had foreknowledge of the eastern disease. He alone could cure him. So, he wanted Smith to treat him.

Question 16.
Who is shot at by the grandfather? Why?
Answer:
The zither-cop was shot at by the grandfather because he was the first to go up the stairs when they heard the sound of a creaking in the attic caused by the grandfather turning in the bed.

Question 17.
What did they do when they witnessed something new in their journey?
Answer:
As they were not specialists, whenever they spotted something new in the sea, they googled and browsed information to learn more about the species.

Question 18.
When did Aditya and the narrator go to Bramhapur?
Answer:
Aditya and the narrator were returning from the site of their new factory at Deodarganj. While returning, in the month of Magha, that is January or February by the English calendar, sometime in the middle of winter, around 3.30 p.m. they went to Bramhapur.

Section – II

Read the following sets of poetic lines and answer any THREE of the following. [3 x 2 = 6]

Question 19.
“She’s today’s woman. Today’s woman dear.
Love her, respect her, keep her near…”
(а) Describe today’s woman according to the poet.
(b) How should a woman be treated?
Answer:
(a) Today’s woman is a woman bom with determination, ready to take risks in life and is strong in her faith and beliefs.
(b) A woman should be treated with love and respect.

Question 20.
“My heart was so light that I sang day and night,
For all nature looked gay. ” “For all nature looked gay”.
“You sang, Sir, you say?
Go then”, says the ant, “and dance the winter away”.”
(а) Explain the phrase, ‘dance winter away’.
(b) The ant tells the cricket to “dance the winter away.” Is the usage of the word . ‘dance’ appropriate here? If so, why?
Answer:
(a) The phrase ‘dance winter away’ means dancing all through the winter season.
(b) The word ‘dance’ here means ‘merry making and wasting time.’ It is appropriate here. The irresponsible cricket does not deserve any sympathy.

Question 21.
“But remember, please, the Law by which we live,
We are not built to comprehend a lie,
We can neither love nor pity nor forgive,
If you make a slip in handling us you die!”
(a) What do you understand by the word, ‘slip’?
(b) What is the Law by which a machine lives?
Answer:
(a) A slip is nothing but a mistake.
(b) The Law is the way in which the machine is designed and programmed to work when the command is given.

Question 22.
“Beneath all uniforms, a single body breathes Like ours: the land our brothers walk upon Is earth like this, in which we all shall lie.”
(a)’ Who is referred to as ‘our brothers’ in this stanza?
(b) What lesson can we learn from these lines?
Answer:
(a) The people who live in countries other than ours have been referred to as our brothers.
(b) These lines teach us the lesson of peace, universal brotherhood and harmony.

Section – III

Answer any THREE of the following. [3 x 2 = 6]

Question 23.
Rewrite the following sentence to the other voice.
Answer:
The novel was read by Mom in one day.
Mom read the novel in one day.

Question 24.
Rewrite using indirect speech.
“How will they get here?” asked Kalyani.
Answer:
Kalyani asked me how they would get here.

Question 25.
Punctuate the following.
If you will sit down said Miranda I will carry your logs the while
“If you will sit down, said Miranda, “I will carry your logs the while

Question 26.
Transform the following sentence into a simple sentence.
Answer:
Unless you work hard you cannot succeed.
You cannot succeed without working hard.

Question 27.
Rearrange the words in the correct order to make meaningful sentences.
(a) her glory / sincere prayers / Kali heard / and appeared / in all / Rama’s / before him
(b) unexpectedly, / instead of / laugh uncontrollably / inspiring awe / made Rama / her form
Answer:
(a) Kali heard Rama’s sincere prayers and appeared before him in all her glory.
(b) Unexpectedly, instead of inspiring awe her form made Rama laugh uncontrollably.

Section – IV

Answer the following. [1 x 2 = 2]

Question 28.
A stranger asks you the way to go to Meenakshi Temple. Help the stranger to reach his/ her destination with the help of the given road-map and write down the steps.
Answer:

• Go straight on N.S.K. Salai and go past the crossroad connecting P.M. Salai.
• After the second left you will come to R.R. Road.
• You will find Meenakshi temple on the opposite side.

Part – III [10 x 5 = 50]
Section-I

Answer any TWO of the following in utmost 10 lines. [2 x 5 = 10]

Question 29.
Was the young seagull same at the beginning and at the end of the lesson? Compare and contrast the two kinds of the same seagull in the lesson.
Answer:
No, the young seagull was not the same bird at the beginning and at the end of the lesson. In the beginning, the young seagull used to be all alone on his ledge. His two brothers and his sister had flown away the day before. He had been afraid of flying with them. Whenever he tried to flap his wings, he was seized with fear. He felt certain that his wings would never support him. His father and mother flew around calling to him shrilly.

They were constantly scolding and taunting him. They were threatening to let him starve on his ledge unless he flew away. However, the young seagull was more confident and sure of his success in the end. Maddened by hunger, he dived at the fish. After trials and errors, his wings spread outwards. He was soaring gradually downwards forgetting all his hesitations and fears. He could float on the ocean now. His success was welcomed by his family. They were praising him now and their beaks were offering him their scraps of dog-fish.
“Positivity ,confidence and persistence are
key in life – so never give up in life.”

Question 30.
“Technology is a boon to the disabled”. Justify.
Answer:
The differently abled, Alisha and David’s life has been transformed because of Technology. It is a boon to the disabled. Assistive technology is designed to help people with disabilities. Typing was impossible, but now Dragon Dictate helps the disabled to speak for words to be printed on screen. Technology can control a computer screen even with Eye Gaze.

Technology is vital to be free and independent. For verbal communication, Liberator Communication Device, with eye movements to communicate verbally is used. It has a Bluetooth adaptor and took a couple of weeks to leam using it. Communicating with people was very difficult before. An ACTIV controller also in the headrest of a mobility chair is used to control TV, Blu-Ray and music players.

Augmentative and Alternative Communication is also the product of technological advancements and a boon to the disabled. EC02 linked to an interactive whiteboard is used to teach PE lessons. Technology also helps control the Play Station, MP3, electric wheelchair and ECO point Eye Gaze to communicate and access the computer. Thus, Technology is a boon to the disabled.
“Technology is not just a tool. It can give learners a voice
that they may not have had before.”

Question 31.
Highlight the factors responsible for the all-women Indian Navy crew to carry out their expedition.
Answer:
The support the crew members received was a major factor. When they knew that they were doing well and looked after themselves well, in spite of all apprehensions they were supportive. The crew members’ personal aim and target mattered a lot. Mostly they wanted to make sure that they complete the journey with ultimate honesty without the use of engines. Than the destination, the journey was important. So their contention was to make sure that they go by the rules of circumnavigation without any means of repulsion and anybody else’s assistance.

The presence of mind and common sense to make decisions and act quickly was an added factor. They had to quickly do an analysis of problem solving techniques. Ego should never come amidst them. Team work helped them to collaborate and work together. Mutual understanding was important too.

One would heat the water while the other would heat the gloves or even rested. Over all the confidence you had in each other than the trust and acceptance as every member of the crew to be a family was a must to carry out the expedition.
“It’s about women helping women and women doing things
together and supporting each other. ”

Question 32.
Give an account of the last day of M. Hamel in school.
Answer:
The story described what was just another ordinary day for Franz who started very late for school that morning. Franz, who played truant with French class, feared M. Hamel’s iron rod. He came to the school thinking he would be punished as he had not leamt his lesson on participles. In fact, he was reluctant to go to school. Initially, he thought of spending the bright warm day outdoors enjoying the chirping of birds and seeing the drilling of Prussian soldiers at the back of the sawmill. On the way, Franz passed the Town hall, where he saw a large crowd reading the bulletin board which had been a source of all bad news. Franz rushed to his classroom, overseeing it for the fear of being chided.

When Franz arrived at the school, his classmates were already seated and the teacher had already started teaching. The back benches were occupied by grim and solemn villagers including the Mayor, The Postmaster, Hauser and many others. To his surprise, M. Hamel was in his Sunday clothes. Franz found M. Hamel to be kinder than usual. Franz was shocked to know that it was the last French lesson and the German teacher would start classes the next day.

He was full of regret for not learning his mother tongue and felt a sudden love for French. He even started liking M. Hamel and forgot all about his ruler. When M. Hamel asked Franz to recite the rules of participle, he was petrified. M. Hamel didn’t scold him and remarked that the only problem with people of

Alsace was procrastinating learning. He blamed parents and himself for exploiting children. Hamel then talked of the French language, calling it the most beautiful language in the world. He said that when we were enslaved knowing our mother tongue was similar to having the key to prison. As the church clock bell struck twelve, M. Hamel with a choked throat wrote on the Blackboard Vive La France!, i.e. Long Live France and dismissed the class.
“Our memories of yesterday will last a lifetime.”

Section – II

Answer any TWO of the following in utmost 10 lines. [2 x 5 = 10]

Question  33.
Give summary of the poem, ‘The Grumble Family’.
Answer:
There is a family that no one ever wants to meet on Complaining Street in ‘Never-are- Satisfied’ city where River Discontent also runs. They growl at everything and hence something goes wrong. Even if their station is high or humble, they are known by the name of Grumble. The weather is always at extreme conditions and they scold at each other at both seasons. Everything is topsy-turvey with people who live on the gloomy Complaining street.

Even when they are satisfied with everything, there isn’t a doubt that they would growl about not having anything to grumble about. The strangest thing is not a single person in the Grumble family can accept the family name because no Grumbler will accept that he is a grumbler nor associated with such qualities. They are so contagious that anyone who says with them for a bit too long become a grumbler himself. Hence, it is wise to keep our feet away from Complaining Street.

Therefore, let us learn to walk with a smile on our lips and a song in our mouth even when things go against our desires. One should never belong to the family of Grumble, even if the status changes drastically.
“Be grateful and you won’t grumble.
Grumble and you won’t be grateful.”

Question  34.
‘Some crickets have four legs and some have two’. Elucidate this statement from the poet’s point of view.
Answer:
The poet is comparing the lazy crickets to the two-legged creatures – the human beings. The poetic device Metaphor is perfectly used to fit into the situation. Everyone knows that crickets have four legs. But he says some have two to compare the silly cricket to the two¬legged human-beings who sometimes are as lazy and silly as the cricket in this poem.

The poet wants to suggest that this story is not entirely a fable; rather, it is related to the real world. Surely, some people are as careless and lazy as the cricket is. Likewise, some humans like the cricket also don’t plan out for the future or for the bad times. They just enjoy the present moment. The poet is thus calling such people as mindless as the cricket.
“God gave us the gift of life; it is up to us to give ourselves the gift of living well.”

Question  35.
Read the following stanza and answer the questions given below.
“If the dim past, nor holding back in fear
From what the future veils; but with a whole
And happy heart, that pays its toll
To Youth and Age, and travels on with cheer.”
(i) Mention the figure of speech in the third line.
(it) Pick out thexontrasting words in the above lines.
(iii) Pick out the rhyming words.
(iv) What is the rhyme scheme of the above lines?
Answer:
(i) Alliteration is the figure of speech in the third line.
(ii) The contrasting words are ‘youth’ and ‘age’
(iii) The rhyming words are fear and cheer; whole and toll.
(iv) The rhyme scheme is abba.

Question  36.
Paraphrase the following stanza.
Beside the house sits a tree.
It never grows leaves,
Not in the winter, spring, summer or fall.
It just sits there, never getting small or ever growing tall,
How could this be?
Answer:
Next to the house, is a tree. The tree too is mysterious like thee house since it has no leaves in any of the seasons. The tree is barren during winter, spring, summer and autumn. The poetess says that the tree just stays there and never grows tall nor becomes short. She wonders how a tree could survive without any leaves or without any growth.

Section – III

Answer any ONE of the following: [1 x 5 = 5]

Question 37.
Rearrange the following sentences in coherent order.
(i) This planet describes its orbit round the sun in 572 years, 194 days, 12 hours, 43 minutes, 9.8 seconds.
(if) One of the Earth Herald’s astronomers had just determined the elements of the new planet Gandini.
(iii) On the whole, Francis Bennett had reason to be satisfied.
(iv) Hurry up and tell the reportage service about it because the public has a passion for these astronomical questions.
(v) Francis Bennett was delighted with such precision.
Answer:
Rearranged number sequence: (iii), (if), (i), (v), (iv)
(iii) On the whole, Francis Bennett had reason to be satisfied.
(ii) One of the Earth Herald’s astronomers had just determined the elements of the new planet Gandini.
(i) This planet describes its orbit round the sun in 572 years, 194 days, 12 hours, 43 minutes, 9.8 seconds.
(v) Francis Bennett was delighted with such precision.
(iv) Hurry up and tell the reportage service about it because the public has a passion for these astronomical questions.

Question 38.
Read the following passage and answer the questions that follow.

One afternoon in the early fall, when Peter was eight years old, his mother called him from his play. “Come, Peter,” she said. “I want you to go across the dike and take these cakes to your friend, the blind man. If you go quickly, and do not stop to play, you will be home again before dark.” The little boy was glad to go on such an errand, and started off with a light heart. He stayed with the poof blind man a little while to tell him about his walk along the dike and about the sun and the flowers and the ships far out at sea. Then he remembered his mother’s wish that he should return before dark and, bidding his friend goodbye, he set out for home.

Questions
(i) Which word indicates it’s the beginning of the season Autumn?
(ii) What did Peter’s mom want him to do?
(iii) Was the little boy happy to obey his mother’s instruction?
(iv) What was the conversation Peter had with his blind friend?
(v) What was the wish of Peter’s mom?
Answer:
(i) The word ‘fall’ indicates the beginning of the season Autumn.
(ii) Peter’s mother wanted Peter to go across the dike and take the cakes to his blind friend.
(iii) Yes, the boy was happy.
(iv) Peter stayed with the poor blind man a little while to tell him about his walk along the dike
and about the sun and the flowers and the ships far out at sea.
(v) Peter’s mom wanted Peter to return home before dark.

Section – IV

Answer any FOUR of the following. [4 x 5 = 20]

Question 39.
Prepare an attractive advertisement using the hints given below. Fans and Air Conditioners – to fan away your sweat- to beat the heat.
Answer:

Question 40.
You are a librarian of Chennai Public School, Chennai. Write a letter to the store manager of a bookseller placing order for some story books in English for the school library.
Answer:
Rishabh Kumar
Chennai Public School
R.K. Puram Chennai
10th May, 2020
The Store Manager .
Indian Book House
Chennai Dear Sir
Sub: Order for stoiy books
I am the librarian of Chennai Public School, R.K. Puram. Please send me the following story books at the address given above. The books should be suitable for the age group of 10 to 14 years. All the books should be sent via VPP as early as possible:

• The Boy in the Dress by David Walliams 10 copies
• Fantastic Mr Fox by Roald Dahl 10 copies
• The Summer of the Swans by Betsy Byars 10 copies
• The Well: David’s Story by Mildred D. Taylor 10 copies

Thanking you
Yours sincerely
Rishabh Kumar Librarian

Address on the envelope
To
Chennai Public School
R.K. Puram
Chennai

Question 41.
You are Pradeep/Asha. As President of the Dramatic Club of your school you have organized an inter-school competition in one-act plays on the occasion of the Silver Jubilee celebrations of your school. Write a notice in about 50 words, informing the students of your school about this proposed event.
Answer:

Question 42.
Write an article in about 150 -200 words on ‘Disaster Management’.
Answer:
Disaster Management
Our country is prone to disasters like floods, drought, cyclones, or earthquakes. We do not . have any clear-cut policy of disaster management nor any force to tackle the situation. Adhoc measures are adopted to cope with every disaster. We wait and watch for others to join the fray. There are heated arguments over jurisdiction—centre or state liability, official assessment and surveys before any help is rushed out to the affected area.

The slow response results in the loss of precious human life and valuable property. We must have clear-cut, well defined guidelines for disaster management. A well-trained task-force having special equipment and trained personnel should be constituted. Its controlling officer should have the authority to  take decisions and ensure their speedy implementation.

Better transport and communication facilities will ensure better results. Bureaucratic set-up should not be allowed to interfere with the work of the disaster-management group.

Question 43.
Make notes or write a summary of the following passage.
The distribution of forests among different districts of the state is very uneven. Concentration of forests is mostly in the hills of western districts and in the Javadi group of hills in Vellore district. Dense forests are also seen in Salem district. More than half of the area in the Nilgiris is under forest. Other districts hold 1% to 5% of area under forests.

Thanjavur being the alluvial plain is suitable for agriculture which has less than 1% of forest cover. The forests of Tamil Nadu have different types of trees. Most of the trees in the state shed their leaves in the dry season. Tamil Nadu has large areas of sandal wood plantations, about 5,88,000 hectares. Hard wood trees are available in the forests of Coimbatore, Nilgiris and Kanyakumari. Trees that are used as fuel are found in Madurai, Coimbatore and Thanjavur districts. Kanyakumari district has rubber plantations.
Notes
Title: Forests in Tamil Nadu
Answer:
Uneven distribution-concentration in western districts, Nilgiris, Javadi hills, Vellore and Salem-other districts have 1-5% forests. Thanjavur only 1% of land under forests.
Different kinds of trees.
Deciduous trees, Hardwood trees, Sandalwood trees and Ordinary trees for firewood available -5,88,000 hectares under sandalwood.
Spread
Hardwood trees-Kanyakumari, Coimbatore and Nilgiris Firewood-Madurai, Thanjavur and Coimbatore Rubber-Kanyakumari

Summary

Title: Forests in Tamil Nadu
Rough Draft
The distribution of forests among different districts of the state is very uneven. Forest cover is dense in šter ditticts, Javadi hills, Vellore, Nilgiris and Salem. Thanjavur has less than 1 % of forest cover. Tamil Nadu forests have hardwood, firewood and sandalwood trees. Sandalwood trees are found in and firewood are found in Kanyakumari, Coimbatore and Thanjavur. Nilgiris has goo oefarciwood, Kanyakumari has rubber plantations. Trees that are used as fuel are found in and Thanjavur districts. Kanyakumari district has rubber plantations.

Fair Draft:
Title: Forests in Tamil Nadu
Forest cover is dense in western districts, Javadi hills, Vellore, Nilgiris and Salem. Thanjavur has less than 1% of forest cover. Tamil Nadu forests have hardwood, firewood and sandalwood trees. Sandalwood trees are found in 5,88,000 hectares. Hardwood and firewood are found in Kanyakumari, Coimbatore and Thanjavur. Nilgiris has good cover of hardwood, Kanyakumari has rubber plantations.
No. of words in the Fair Draft: 57

Question 44.
Identify and correct the errors in the following sentences.
(a) The State of Karnataka, is unarguably the cradle of banking on the country.
(b) If tomorrow is declared a holiday we shall go to a one day trip.
(c) My grandfather used to go for walk every morning.
(d) Darleena and me are like sisters but from different parents.
(e) She said that she will mind if I refused her offer.
Answer:
(a) The State of Karnataka, is unarguably the cradle of banking in the country.
(b) If tomorrow is declared a holiday we shall go for a one day trip.
(c) My grandfather used to go for a walk every morning.
(d) Darleena and I are like sisters but from different parents.
(e) She said that she would mind if I refused her offer.

Section – V

Quote from memory. [1 x 5 = 5]

Question 45.
Remember, we who countries strange.
Answer:
Remember, we who take arms against each other
It is the human earth that we defile.
Our hells of fire and dust outrage the innocence
Of air that is everywhere our own,
Remember, no men are foreign, and no countries strange.

Part – IV

Write a paragraph of about 150 words by developing the following hints. [2 x 8 = 16]

Question 46.
(a) Prospero overthrown – teenage daughter – isolated island – marooned – companion Ariel, Caliban – appropriated by Antonio – King of Naples – Ferdinand, Antonio – wrecked in sea storm – Prospero’s orders – invisible and spy – Miranda sees Ferdinand – plan works – test Ferdinand’s loyalty – menial tasks – pleasant – propose marriage – shipwrecked crew’ grieve – magical delicious banquet – Ferdinand and Miranda marry.
Answer:
The plot in the play, The Tempest, revolves around Prospero enacting his revenge on various characters who have wronged him in different ways. There was an island in the sea, the only inhabitants of which were an old man, named Prospero, and his daughter Miranda, a very beautiful young lady. She came to this island so young. Prospero had released many good spirits from a witch called Sycorax who had them imprisoned in the bodies of large trees.

These gentle spirits were ever after obedient to the will of Prospero. He creates a sea storm and makes the vessel to toss and shipwreck the crew and sends Ariel to check on his brother and other inmates of the ship. Every member thinks that he is the only one saved. Meanwhile, Ferdinand is brought before Prospero. Miranda wonders what kind of a creature he was as she has not seen any other human beings on the island. Instantly they fall in love for each other. Prospero realises their love and tests Ferdinand’s love for his daughter giving him menial tasks.

Ferdinand is found worthy by Prospero. In the end Antonio finally meets Prospero, he feels remorse for his deeds and begs pardon from Prospero. Prospero forgives him and they all leave to Milan and the wedding of Miranda and Ferdinand commences with delicious banquets.

[OR]

(b) According to the list kept in the Bible, develop the given hints and say what you can infer of Uncle Philip’s collection of stones.
Toni’s fear – iron box explosion – found in his uncle’s Bible – list of the stones, cost – dated two years before uncle’s death – well known – enormous value – curious histories – Empress-Queen Maria Theresa – Blood ruby – murders – unequalled collection – black pearl – queer.

One fine day when Tom was already groping in fear that the iron box may explode with careless handling by someone, found between the leaves of his uncle’s Bible, a numbered list of the stones with their cost. It was dated two years before his uncle’s death. Many of the stones were well known, and their enormous value was also mentioned. Several of the rubies were described with care and curious histories of them were given in detail.

One was said to be the famous “Sunset ruby,” which had belonged to the Empress-Queen Maria Theresa. One was called the “Blood ruby,” not because of the colour but on account of the murders it had occasioned. The pearls were described with care as an unequalled collection. Concerning two of them, they seemed to have done much evil and some good. One, a black pearl, was mentioned in an old bill of sale which seemed queer.

Question 47.
Read the following passage and answer the questions given below:
Answer:
A long time ago there lived a monster called the sphinx. She had the head of a woman, the body of a lion and the wings of a big bird. Her eyes were so fierce that nobody dared to look at her face. The sphinx sat on a cliff outside the city of Thebes. When a man passed by her, she would ask him a riddle. The man had to give the right answer, or the sphinx would eat him up. The riddle was so difficult that no one could answer it. Many men lost their lives and people were afraid to come out of their houses. Then one day a clever man wanted to answer the sphinx.

His name was Oedipus and he was not afraid of the sphinx. The sphinx stopped and asked him a riddle “what walks on four legs in the morning, on two legs at noon and on three legs in the evening?”Oedipus said that it was easy. “You try and answer it!” roared the sphinx. Oedipus said, “The answer is man walks on four legs in his childhood, on two legs when grown up and on three legs during old age”. Hearing the right answer the sphinx was disappointed and very angry. She jumped off the cliff and ended her life.

Questions.
(a) How did the sphinx look like?
(b) What would the sphinx do if a man failed to give the right answer to her riddle?
(c) Why was the sphinx angry?
(d) What is the ‘third leg’ of man in his old age?
Answer:
(a) The sphinx looked like a monster with the head of a woman, the body of a lion and the wings of a big bird.
(b) The sphinx would eat up the man if he failed to give the right answer to her riddle.
(c) Hearing the right answer to her riddle from Oedipus, the sphinx was disappointed and very angry
(d) The third leg is invariably the walking stick the old man will be using in his old age.

[OR]

Read the following poem and answer the questions given below:
Mother India
Is there aught you need that my hands withhold.
Rich gifts of raiment or grain of gold?
Lo! I have clung to the East and West Priceless treasures tore from my breast.
And yielded the sons of my stricken womb To the drum – beats of duty, the sabres of doom.
Gathered like pearls in their alien graves Silent they sleep by the Persian waves,
Scattered like shells on Egyptian sands.
They lie with pale brows and brave, broken hands They are strewn like blossoms mown down by chance On the blood-brown meadows of Flanders and France.
Can ye measure the grief of the tears I weep Or compass the woe of the watch I keep?
Or the pride that trills thro’ my heart’s despair And the hope that comforts the anguish of prayer?
And the far and glorious vision I see Of the torn red banners of victory?
When the terror and tumult of hate shall cease And life be refashioned on anvils of peace,
And your love shall offer memorial thanks
To the comrades who fought in your dauntless ranks,
And your honour the deeds of the deathless ones,
Remember the blood of my martyred sons!

Questions.
(a) Why is Mother India proud?
(b) State Mother India’s vision of a new world.
(c) What does Mother India expect?
(d) Pick out words from the poem which is equivalent to
(i) commotion
(ii) friends.
Answer:
(a) Mother India is proud because of her sons’ supreme sacrifice that eternalizes them forever.
(b) Mother India envisions a new world based on peace, love and understanding.
(c) Mother India expects the world to remember the sacrifices made by her sons in the World War with gratitude.
(d) (i) Commotion – tumult
(ii) Friends – comrades

Students can Download Samacheer Kalvi 10th Science Model Question Paper 1 English Medium Pdf, Samacheer Kalvi 10th Science Model Question Papers helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams.

Tamil Nadu Samacheer Kalvi 10th Science Model Question Paper 1 English Medium

General Instructions:

1. The question paper comprises of four parts
2. You are to attempt all the questions in each part. An internal choice of questions is provided wherever applicable.
3. All questions of Part I, II, III and IV are to be attempted separately.
4. Question numbers 1 to 12 in Part I are Multiple Choice Questions of one mark each.
   These are to be answered by writing the correct answer along with the corresponding option code.
5. Question numbers 13 to 22 in Part II are of two marks each. Any one question should be answered compulsorily.
6. Question numbers 23 to 32 in Part III are of four marks each. Any one question should be answered compulsorily.
7. Question numbers 33 to 35 in Part IV are of seven marks each. Draw diagrams wherever necessary.

Time: 3 Hours
Maximum Marks: 75

Part – I

(i) Answer all the questions. [12 × 1 = 12]
(ii) Choose the most suitable answer and write the code with the corresponding answer.

Question 1.
Newton’s III law is applicable ________ .
(a) for a body is at rest
(b) for a body in motion
(c) both a and b
(d) only for bodies with equal masses
Answer:
(c) both a and b

Question 2.
SI unit of resistance is ________.
(a) mho
(b) joule
(c) Ohm
(d) Ohm meter
Answer:
(c) Ohm

Question 3.
Which of the following is the heaviest one?
(a) Hydrogen
(b) Alpha
(c) Beta
(d) Gamma
Answer:
(b) Alpha

Question 4.
1 mole of any substance contains ________ molecules.
(a) 6.023 × 10²³
(b) 6.023 × 10^-23
(c) 3.0115 × 10²³
(d) 12.046 × 10²³
Answer:
(a) 6.023 × 10²³

Question 5.
In the alumino thermic process the role of Al is ________
(a) Oxidizing agent
(b) reducing agent
(c) hydrogeneration agent
(d) Sulphurising agent
Answer:
(b) reducing agent

Question 6.
Solubility is the amount of solid dissolved in ________ g of solvent.
(a) 10 g
(b) 50 g
(c) 100 g
(d) 1 g
Answer:
(c) 100 g

Question 7.
Heart of heart is called ________.
(a) SA node
(b) Purkinjee fibres
(c) AV node
(d) Bundle of His
Answer:
(a) SA node

Question 8.
Metastasis is associated with ________.
(a) Benign tumour
(b) Malignant tumour
(c) Both (a) and (b)
(d) Crown gall tumour
Answer:
(b) Malignant tumour

Question 9.
Kreb’s cycle takes place in ________.
(a) Chloroplast
(b) Stomata
(c) Inner mitochondrial membrane
(d) Mitochondrial matrix
Answer:
(d) Mitochondrial matrix

Question 10.
The endarch condition is the characteristic feature of ________.
(a) root
(b) stem
(c) leaves
(d) flower
Answer:
(b) stem

Question 11.
Palaeontology deals with the study of ________.
(a) fossils
(b) genes
(c) petroleum
(d) homologous organ
Answer:
(a) fossils

Question 12.
Which software is used to create animation?
(a) Paint
(b) PDF
(c) MS word
(d) Scratch
Answer:
(d) Scratch

Part – II

Answer any seven questions. (Q.No: 22 is compulsory) [7 × 2 = 14]

Question 13.
State the principle of Moments.
Answer:
When a number of like or unlike parallel forces act on a rigid body and the body is in equilibrium, then the algebraic sum of the moments in the clockwise direction is equal to the algebraic sum of the moments in the anti-clockwise direction.

Question 14.
Why does the sky appear in blue colour?
Answer:
When sunlight passes through the atmosphere, the blue colour is scattered to a greater extent than the red colour. This scattering causes the sky to appear in blue colour.

Question 15.
What is the audible range of frequency?
Answer:
Audible waves – These are sound waves with a frequency ranging between 20 Hz to 20,000 Hz.

Question 16.
What is meant by binary solution?
Answer:
A solution must at least be consisting of two components. Such solutions which are made of one solute and one solvent are called binary solutions, (e.g.) adding CuSO₄ crystals to water.

Question 17.
Differentiate reversible and irreversible reactions.
Answer:
Reversible Reaction:

• Reaction can be reversed.
• It proceeds in both directions.
• It attains equilibrium.
• It is relatively slow.

Irreversible Reaction:

• Reaction cannot be reversed.
• It is unidirectional.
• Equilibrium is not attained.
• It is fast.

Question 18.
What are viviparous animals?
Answer:
The animals which give birth to young ones are called viviparous animals.

Question 19.
Bring out any two physiological activities of abscisic acid (ABA).
Answer:

1. ABA promotes the process of abscission. (Separation of leaves, flowers and fruits from the branch)
2. During water stress and drought conditions ABA causes stomatal closure.

Question 20.
Define triple fusion.
Answer:
The fusion involving two polar nucleus and a sperm nucleus, that occurs in double fertilization in a seed plant and results in the formation of endosperm is called the triple fusion.

Question 21.
Why is Archaeopteryx considered to be connecting link?
Answer:
Archaeopteryx is the oldest known fossil bird. It is considered to be a connecting link between reptiles and birds. It had wings with feathers like a bird. It had long tail, clawed digits and conical teeth, like a reptile.

Question 22.
Calculate the resistance of a conductor through which a current of 5A passes, when the potential difference between its ends is 60V.
Answer:
Given, I = 5A
V = 60 V
From Ohm’s law: R = \(\frac{V}{I}=\frac{60}{5}\) =12 Ω
∴ R = 12 Ω

Part – III

Answer any seven questions (Q.No: 32 is compulsory) [7 × 4 = 28]

Question 23.
State the universal law of gravitation and derive its Mathematical expression.
Answer:

This law states that every particle of matter in this universe attracts every other particle with a force. This force is directly proportional to the product of their masses and inversely proportional to the square of the distance between the centres of there masses. The direction of the force acts along the line joining the masses.

Force between the masses is always attractive and it does not depend on the medium where they are placed. Let m₁ and m₂ be the masses of two bodies A and B placed r metre apart in space

Force, F ∝ m₁ × m₂, F ∝ \(\frac{1}{r^{2}}\)
On combining the above two expressions,
F ∝ \(\frac{m_{1} \times m_{2}}{r^{2}}\)
F = \(\frac{G m_{1} m_{2}}{r^{2}}\)
Where G is the universal gravitational constant. Its value in SI unit is 6.674 × 10^-11 N m² kg^-2.

Question 24.
(i) List any five properties of light.
Answer:

• Light is a form of energy.
• Light always travel along a straight line.
• Light does not need any medium for its propagation. It can even travel through vacuum.
• The speed of light in vacuum or air is C = 3 x 10⁸ ms^-1
• Different coloured light has different wavelength and frequency.

(ii) State Rayleigh’s law of scattering.
Answer:
Rayleigh’s scattering law states that “The amount of scattering of light is inversely proportional to the fourth power of its wavelength”.
Amount of scattering S ∝ \(\frac{1}{\lambda^{4}}\)

Question 25.
(i) A torch bulb is rated at 3V and 600 mA. calculate it’s (a) power (b) resistance (c) energy consumed if it is used for 4 hours.
Answer:
Given
V = 3V
I = 600 mA = 600 × 10^-3 A
(a) Power (P) = VI = 3 × 600 × 10^-3 = 1800 × 10^-3
P= 1.8 W (or) watt.

(b) Resistance (R) = \(\frac{V}{I}\)

R = 5 Ω

(c) Power (P) = 1.8 W and t = 4 hours
= 4 × 60 × 60 = 14400 second.
Energy consumed (E) = P × t
= 1.8 × 14400 = 25920 joules
E = 25.9 Wh

(ii) Why does sound travel faster on a rainy day than on a dry day?
Answer:
When humidity increases the speed of sound increases. That is why we can hear sound from long distances clearly during rainy season.

Question 26.
Give the salient features of “Modern atomic theory”.
Answer:
The Salient features of “Modern atomic theory” are:

• An atom is no longer indivisible.
• Atoms of the same element may have different atomic masses.
• Atoms of different elements may have same atomic masses.
• Atoms of one element can be transmuted into atom of other elements. In other words, atom is no longer indestructible.
• Atoms may not always combine in a simple whole number ratio.
• Atom is the smallest particle that takes part in a chemical reaction.
• The mass of an atom can be converted into energy E = mc².

Question 27.
How is Aluminium extracted from Bauxite?
Answer:
Bauxite is the chief ore of aluminium. The extraction of aluminium from bauxite involves two steps:
(1) Conversion of bauxite into alumina – Baeyer’s process.
The conversion of Bauxite into Alumina involves the following steps:
Bauxite ore is finely ground and heated under pressure with a solution of concentrated caustic soda at 150° C to obtain sodium meta aluminate.

On diluting sodium meta aluminate with water, a precipitate of aluminium hydroxide is formed. The precipitate is filtered, washed, dried and ignited at 1000°C to get alumina.

(2) Electrolytic reduction of alumina – Hall’s process.
Aluminium is produced by the electrolytic reduction of fused alumina (Al₂O₃) in the electrolytic cell.
Cathode: Iron tank linked with graphite
Anode: A bunch of graphite rods suspended in molten electrolyte.
Electrolyte:

Pure alumina + molten cryolite + fluorspar

Temperature: 900 – 950° C
Voltage used: 5 – 6 V
Overall reaction:
2 Al₂O₃ → 4 Al + 3 O₂ ↑

Question 28.
What are the structures involved in the protection of brain?
Answer:
The brain, controlling centre of all the body activities is covered by three connective tissue membrane (or) meninges.

• Duramater – is the outermost thick fibrous membrane.
• Arachnoid membrane – is the middle thin vascular membrane providing web-like cushion.
• Piamater – is the innermost thin delicate membrane richly supplied with blood. Meningeal membranes protect the brain from mechanical injury.

Question 29.
(a) Why did Mendel select pea plant for his experiment?
Answer:

• The pea plant is self pollinating and so it is very easy to raise pure breeding individuals.
• It has a short life span.
• It is easy to cross pollinate.
• It has deeply defined contrasting characters.
• The flowers are bisexual.

(b) What is the importance of valves in the heart?
Answer:
The valves are the muscular flaps, that regulate the flow of blood in a single direction and prevent backward flow of blood.

Question 30.
Differentiate the following:
(i) Light dependent reaction and Light independent reaction
Answer:
Light dependent reaction:

• It is called Hill reaction or Light reaction.
• The reaction is earned out in Thylakoid membranes of the chloroplast.
• It is carried out in the presence of light.
• Photosynthetic pigments absorb the light energy and convert it into chemical energy ATP and NADPH₂.

Light independent reaction:

• It is called Dark reaction or Biosynthetic pathway or Calvin cycle.
• This reaction is carried out in the stroma of the chloroplast.
• It is carried out in the absence of light.
• CO₂ is reduced into carbohydrates with the help of light generated ATP and NADPH₂.

(ii) Aerobic and Anaerobic respiration
Answer:
Aerobic:

• Occur in the presence of oxygen.
• Carbon dioxide, water and ATP are produced.

Anaerobic:

• Occur in the absence of oxygen.
• Lactic acid, Ethanol and ATP are produced.

Question 31.
(a) What is metastasis?
Answer:
The cancerous cells migrate to distant parts of the body and affect new tissues and this process is called Metastasis.

(b) What are the effects of hybrid vigour in animals?
Answer:
The superiority of the hybrid, obtained by cross breeding is called heterosis or hybrid vigour.
Effects of hybrid vigour:

• Increased production of milk by cattles.
• Increased production of egg by poultry.
• High quality of milk is produced.
• Increased growth rate in domesticated animals.

Question 32.
(i) Explain Soddy and Fajan Radioactive displacement law.
Answer:
Alpha decay:
(a) Unstable parent nucleus emits an alpha particle to form stable daughter nucleus.
(b) ₉₂U²³⁸ → ₉₀Th²³⁴ + ₂He⁴ ( α – decay ).
(c) Mass number decreases by 4.
(d) Atomic number decreases by 2.

Beta decay:
(a) Unstable parent nucleus emits a beta particle to form stable daughter nucleus.
(b) ₁₅P³² → ₁₆S³² + _-1e⁰ (β – decay)
(c) Mass number – no change.
(d) Atomic number increased by 1.

Gamma decay:
(a) The atomic number and the mass number remain same.
(b) The energy level of the nucleus change. .

(ii) Calculate the pH of 0.05M H₂SO₄.
[H⁺] = Normality = Molarity × basicity
= 0.05 × 2 = 0.1
= 10^-1 = 1 × 10^-1
pH = -log₁₀ [H⁺]
pH = -log₁₀ 1 × 10^-1
pH = -log₁₀ 1 – log 10^-1
pH = 0 – (- 1 log₁₀ 10) = 1

Part – IV

Answer all the questions. [3 × 7 = 21]

Question 33.
(a) (i) State the law of volume.
Answer:
When the pressure of gas is kept constant, the volume of a gas is directly proportional to the temperature of the gas.
(i.e.,) V ∝ T .
\(\frac{V}{T}\) = constant

(ii) Derive the ideal gas equation.
Answer:
The ideal gas equation is an equation, which relates all the properties of an ideal gas. An ideal gas obeys Boyle’s law, Charles’ law and Avagadro’s law,
According to Boyle’s law
PV = constant ……… (1)
According to Charles’s law,
\(\frac{V}{T}\) = constant …….(2)
According to Avagadro’s law,
\(\frac{V}{n}\) = constant ……(3)
After combining equations (1), (2) and (3)
\(\frac{P V}{n T}\) = constant ……..(4)

The above relation is called combined law of gases. If you consider a gas, which contains μ moles of the gas, the number of atoms contained will be equal to (i times the Avagadro’s number, NA
(i.e.,) n = μ N_A
using equation (5) equation (4) can be written as
PV / μ N_A T = constant

The value of the constant in the above equation is taken to be k_B, which is called as Boltzmann constant (1.38 × 10^-23 J K^-1). Hence, we have the following equation,
PV / μ N_A T = kB
PV = μ N_A k_B T
Here μ N_A k_B = R, which is termed as universal gas constant whose value is 8.31 Jmol^-1_1K^-1
PV = RT
Ideal gas equation is also called as equation of state because it gives the relation between the state variables and it is used to describe the state of any gas.

[OR]

(b) (i) A man is standing between two vertical walls 680 m apart. He claps his hands and hears two distinct echoes after 0.9 seconds and 1.1 seconds respectively. What is the speed of sound in the air?
Answer:

(ii) A door is pushed, at a point whose distance from the hinges is 90 cm, with a force of 40 N. Calculate the moment of the force about the hinges.
Answer:
The moment of a force M = F × d
F = 40 N
d = 90 cm = 0.9 m
Hence, moment of the force = 40 × 0.9 = 36 Nm

Question 34.
(a) (i) Calculate the mass of 2.5 mole of oxygen atom.
Answer:
Number of moles = \(\frac{\text { Mass }}{\text { Atomic mass }}\)
∴ Mass = Number of moles × Atomic mass
= 0.5 × 16 = 8 g

(ii) Calculate the number of molecules in 11g of CO₂.
Answer:
Gram Molecular of CO₂ = 44 g.
number of molecules in 44 g of CO₂ = 6.023 × 10²³
number of molecules in 11 g of CO₂ = \(\frac{6.023 \times 10^{23}}{44}\) × 11
= 1.53 × 10²³ molecules

(iii) Calculate the number of moles in 81g of aluminium.
Answer:
Number of moles = \(\frac{\text { Mass }}{\text { Atomic mass }}\)
= \(\frac{81}{27}\) = 3 moles

[OR]

(b) How is ethanol manufactured from sugar-cane?
Answer:
Molasses is a dark coloured syrupy liquid left after the crystallization of sugar from the concentrated sugarcane juice. It contains 30 % of Sucrose, which cannot be separated by crystallization.

(i) Dilution of Molasses:
Molasses is first diluted with water,to bring down the concentration of sugar to about 8 to 10 percent.

(ii) Addition of Nitrogen Source:
Molasses contains enough nitrogenous matter to act as food for yeast during the fermentation process. If the nitrogenous matter is poor, ammonium sulphate or ammonium phosphate is added.

(iii) Addition of yeast:
This solution kept in large fermentation tank and yeast is added to it kept at about 303K for a few days. During this period, the enzymes invertase and Zymase present in yeast, convert sucrose into ethanol.

The fermented liquid is technically called wash.

(iv) Distillation of wash:
This wash containing 15 to 18% alcohol, is now subjected to fractional distillation. The main fraction drawn is an aqueous solution of ethanol which contains 95.5% of ethanol and 4.5% of water. This is called rectified spirit. This mixture is then refluxed over quicklime for about 5 to 6 hour and then allowed to stand for 12 hours. On distillation of mixture pure alcohol (100%) is obtained. This is called absolute alcohol.

Question 35.
(a) (i) Which hormone requires iodine for its formation? What will happen if intake of iodine in our diet is low?
Answer:
The formation of Thyroxine (T₄) and Triiodothyronine requires iodine. If there is an inadequate supply of iodine in our diet it leads to enlargement of thyroid gland called goitre.

(ii) What is the importance of rainwater harvesting?
Answer:
The importance of rainwater harvesting is as follows:

• Overcome the rapid depletion of ground water level.
• To meet the increased demand of water.
• Reduces flood and soil erosion.
• Water stored in ground is not contaminated by human and animal wastes and hence can be used for drinking purposes.

(iii) What is colostrum? How is milk production hormonally regulated?
Answer:
The first fluid which is produced from the mammary gland after child birth is called colostrum. Milk production from alveoli of mammary gland is stimulated by prolactin secreted from anterior pituitary.

[OR]

(b) (i) How does locomotion take place in leech?
Answer:
Locomotion in leech takes place by:

• Looping or crawling movement: Crawling movement is brought about by the contraction and relaxation of muscles. The two suckers serve for attachment during movement.
• Swimming movement: Leeches swim very actively and perform undulating movement in water.

(ii) How does Fossilization occur in plants?
Answer:
Fossilization in plants: The process of formation of fossil in the rocks is called fossilization.
The common methods of fossilization includes:

1. Petrifiction: Minerals like silica slowly penetrate in and replace the original organic tissue. This method can preserve hard and soft parts, (e.g.) wood fossils.

2. Mold and Cast: A replica of a plant or animal is preserved in sedimentary rocks. When the organism get buried in sediment it is dissolved by underground water leaving a hollow depression called Mold. It shows only the original shape and not the internal structure. Minerals or sediments fill the hollow depression and forms a cast.

3. Preservation: The entire plant may be preserved to protect from the organism from decay. Ice or amber (tree sap) can be used for preservation.

4. Compression: When the organism dies, the hard parts settle at the bottom of the sea bed and are covered by sediment. The process goes on continuously and the fossils are formed.

5. Infiltration: The precipitation of minerals takes place which later on infiltrate the cell wall. The process is brought about by several mineral element such as silica, calcium carbonate and magnesium carbonate.