Acids Bases and Salts

1. What happens when a solution of an acid is mixed with a solution of a base in a test tube? (i) Temperature of the solution decreases (ii) Temperature of the solution increases (in) Temperature of the solution remains the same (iv) Salt formation takes place (a) (i) and (iv) (b) (i) and (iii) (c) (ii) only (d) (ii) and (iv)

Answer

Answer: d

2. When hydrogen chloride gas is prepared on a humid day, the gas is usually passed through the guard tube containing calcium chloride. The role of calcium chloride taken in the guard tube is to (a) absorb the evolved gas (b) moisten the gas (c) absorb moisture from the gas (d) absorb Cl– ions from the evolved gas

Answer/ Explanation

Answer: c Explaination: Reason: Guard tube drys (absorbs water) from calcium chloride on a humid day.

3. Which one of the following salts does not con-tain water of crystallisation? (a) Blue vitriol (b) Baking soda (c) Washing soda (d) Gypsum

Answer

Answer: b

4. In terms of acidic strength, which one of the following is in the correct increasing order? (a) Water < Acetic acid < Hydrochloric acid (b) Water < Hydrochloric acid < Acetic acid (c) Acetic acid < Water < Hydrochloric acid (d) Hydrochloric acid < Water < Acetic acid

Answer

Answer: a

5. What is formed when zinc reacts with sodium hydroxide? (a) Zinc hydroxide and sodium (b) Sodium zincate and hydrogen gas (c) Sodium zinc-oxide and hydrogen gas (d) Sodium zincate and water

Answer/ Explanation

Answer: b Explaination: Reason: Zn + 2NaOH → Ma2Zn02 (Sodium Zincate) + H2

6. Tomato is a natural source of which acid? (a) Acetic acid (b) Citric acid (c) Tartaric acid (d) Oxalic acid

Answer

Answer: d

7. Brine is an (a) aqueous solution of sodium hydroxide (b) aqueous solution of sodium carbonate (c) aqueous solution of sodium chloride (d) aqueous solution of sodium bicarbonate

Answer

Answer: c

8. Na2CO3 . 10H2O is (a) washing soda (b) baking soda (c) bleaching powder (d) tartaric acid

Answer

Answer: a

9. At what temperature is gypsum heated to form Plaster of Paris? (a) 90°C (b) 100°C (c) 110°C (d) 120°C

Answer

Answer: b

10. How many water molecules does hydrated cal-cium sulphate contain? (a) 5 (b) 10 (c) 7 (d) 2

Answer/ Explanation

Answer: d Explaination: Reason: Chemical formula of hydrated calcium sulphate or gypsum is CaSO4.2H2O

11. Sodium carbonate is a basic salt because it is a salt of a (a) strong acid and strong base (b) weak acid and weak base (c) strong acid and weak base (d) weak acid and strong base

Answer

Answer: d

12. Alkalis are (a) acids, which are soluble in water (b) acids, which are insoluble in water (c) bases, which are insoluble in water (d) bases, which are soluble in water

Answer

Answer: d

13. Which of the following statements is correct about an aqueous solution of an acid and of a base? (i) Higher the pH, stronger the acid (ii) Higher the pH, weaker the acid (in) Lower the pH, stronger the base (iv) Lower the pH, weaker the base (a) (i) and (iii) (b) (ii) and (iii) (c) (i) and (iv) (d) (ii) and (iv)

Answer/ Explanation

Answer: d Explaination: Reason: Stronger the acid, lesser is the pH. Stronger the base, higher is the pH.