Acid, Base & Salt

NCERT Exemplar Solution:MCQs2

Question: 11. Common salt besides being used in kitchen can also be used as the raw material for making

1. washing soda
2. bleaching powder
3. baking soda
4. slaked lime

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

Answer: (c) (i) and (iii)

Explanation: Washing soda and Baking soda are prepared by Solvay process using sodium chloride (common salt).

Question: 12. One of the constituents of baking powder is sodium hydrogencarbonate, the other constituent is

1. hydrochloric acid
2. tartaric acid
3. acetic acid
4. sulphuric acid

Answer: (b) Tartaric acid

Explanation: Baking powder is formed by the reaction of sodium hydrogen carbonate (baking soda) and tartaric acid (edible acid).

Thus, constituent other than sodium hydrogen carbonate is tartaric acid.

Question: 13. To protect tooth decay we are advised to brush our teeth regularly. The nature of the tooth paste commonly used is

1. acidic
2. neutral
3. basic
4. corrosive

Answer: (c) basic

Explanation: Tooth paste contains mild base which neutralizes acid produced by bacteria present in mouth. This prevents corrosion of tooth enamel.

Question: 14. Which of the following statements is correct about an aqueous solution of an acid and of a base?

1. Higher the pH, stronger the acid
2. Higher the pH, weaker the acid
3. Lower the pH, stronger the base
4. Lower the pH, weaker the base

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

Answer: (d) (ii) and (iv)

Explanation: Strength of acid increases with decrease in value of pH from 7 while strength of base increases with increase in value of pH from 7.

Question: 15. The pH of the gastric juices released during digestion is

1. less than 7
2. more than 7
3. equal to 7
4. equal to 0

Answer: (a) less than 7

Explanation: Gastric juice is acidic. Thus, pH value of gastric juice is less than 7.

Question: 16. Which of the following phenomena occur, when a small amount of acid is added to water?

1. Ionisation
2. Neutralisation
3. Dilution
4. Salt formation

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

Answer: (b) (i) and (iii)

Explanation: When acid is added to water, it dissociates into ions. And water is added to dilute acid.

Question: 17. Which one of the following can be used as an acid–base indicator by a visually impared student?

1. Litmus
2. Turmeric
3. Vanilla essence
4. Petunia leaves

Answer: (c) Vanilla essence

Explanation: Vanilla is an olfactory indicator, which vanishes its smell with base. Thus, it is used by a visually impared student.

Question: 18. Which of the following substance will not give carbon dioxide on treatment with dilute acid?

1. Marble
2. Limestone
3. Baking soda
4. Lime

Answer: (d) Lime

Question: 19. Which of the following is acidic in nature?

1. Lime juice
2. Human blood
3. Lime water
4. Antacid

Answer: (a) Lime juice

Explanation: Except Lime juice all are basic in nature. Normal human blood is slightly alkaline in nature. 

Question: 20. In an attempt to demonstrate electrical conductivity through an electrolyte, the following apparatus

1. Bulb will not glow because electrolyte is not acidic
2. Bulb will glow because NaOH is a strong base and furnishes ions for conduction.
3. Bulb will not glow because circuit is incomplete
4. Bulb will not glow because it depends upon the type of electrolytic solution

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

Answer: (c) (ii) only