Acid, Base & Salt

NCERT Exemplar Solution:MCQs3

Question: 21. Which of the following is used for dissolution of gold?

1. Hydrochloric acid
2. Sulphuric acid
3. Nitric acid
4. Aqua regia

Answer: (d) Aqua regia

Explanation: Aqua regia dissolved gold.

Question: 22. Which of the following is not a mineral acid?

1. Hydrochloric acid
2. Citric acid
3. Sulphuric acid
4. Nitric acid

Answer: (b) Citric acid

Explanation: Other acids than citric acid are mineral acids.

Question: 23. Which among the following is not a base?

1. NaOH
2. KOH
3. NH4OH
4. C₂H₅ OH

Answer: (d) C₂H₅ OH

Explanation: C₂H₅ OH is ethyl alcohol and not a base.

Question: 24. Which of the following statements is not correct?

1. All metal carbonates react with acid to give a salt, water and carbon dioxide
2. All metal oxides react with water to give salt and acid
3. Some metals react with acids to give salt and hydrogen
4. Some non metal oxides react with water to form an acid

Answer: (b) All metal oxides react with water to give salt and acid.

Question: 25. Match the chemical substances given in Column (A) with their appropriate application given in

1. A–(ii), B–(i), C–(iv), D–(iii)
2. A–(iii), B–(ii), C–(iv), D–(i)
3. A–(iii), B–(iv), C–(i), D–(ii)
4. A–(ii), B–(iv), C–(i), D–(iii)

Answer: (c) A – (iii), B – (iv), C – (i), D – (ii)

Question: 26. Equal volumes of hydrochloric acid and sodium hydroxide solutions of same concentration are mixed and the pH of the resulting solution is checked with a pH paper. What would be the colour obtained? (You may use colour guide given in Figure 2.2

1. Red
2. Yellow
3. Yellowish green
4. Blue

Answer: (c) Yellowish green

Explanation: Hydrochloric acid and sodium hydroxide neutralizes each other and pH of the resulting solution will be 7. Thus, option (c) Yellowish green is the correct answer.

Question: 27. Which of the following is(are) true when HCl (g) is passed through water?

1. It does not ionise in the solution as it is a covalent compound.
2. It ionises in the solution
3. It gives both hydrogen and hydroxyl ion in the solution
4. It forms hydronium ion in the solution due to the combination of hydrogen ion with water molecule

1. (i) only
2. (iii) only
3. (ii) and (iv)
4. (iii) and (iv)

Answer: (c) (ii) and (iv)

Question: 28. Which of the following statements is true for acids?

1. Bitter and change red litmus to blue
2. Sour and change red litmus to blue
3. Sour and change blue litmus to red
4. Bitter and change blue litmus to red

Answer: (c) Sour and change blue litmus to red

Question: 29. Which of the following are present in a dilute aqueous solution of hydrochloric acid?

1. H₃O⁺ + Cl^—
2. H₃O⁺ + OH^—
3. C^—– + OH^—
4. unionised HCl

Answer: (a) H₃O⁺ + Cl^—

Question: 30. Identify the correct representation of reaction occurring during chloralkali process

1. 2NaCl(l) + 2H₂O(l) → 2NaOH(l) + Cl₂ (g) + H₂ (g)
2. 2NaCl(aq) + 2H₂O(aq) → 2NaOH(aq) + Cl₂ (g) + H₂ (g)
3. 2NaCl(aq) + 2H₂O(l) → 2NaOH(aq) + Cl₂ (aq) + H₂ (aq)
4. 2NaCl (aq) + 2H₂O (l) → 2NaOH (aq) + Cl₂ (g) + H₂ (g)

Answer: (d) 2NaCl (aq) + 2H₂O (l) → 2NaOH (aq) + Cl₂ (g) + H₂ (g)