Acid Base and Salt
NCERT Exemplar Solution MCQ 1
What happens when a solution of an acid is mixed with a solution of a base in a test tube?
- The temperature of the solution increases.
- The temperature of the solution decreases.
- The temperature of the solution remains the same.
- Salt formation takes place
- (i) only
- (i) and (iii)
- (ii) and (iii)
- (i) and (iv)
Answer: (d) (i) and (iv)
An aqueous solution turns red litmus solution blue. Excess addition of which of the following solution would reverse the change?
- Baking powder
- Ammonium hydroxide solution
- Hydrochloric acid
Answer: (d) Hydrochloric acid
During the preparation of hydrogen chloride gas 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
- absorb the evolved gas
- moisten the gas
- absorb moisture from the gas
- absorb Cl− ions from the evolved gas
Answer: (c) absorb moisture from the gas
Which of the following salts does not contain water of crystallisation?
- Blue vitriol
- Baking soda
- Washing soda
Answer: (b) Baking soda
Sodium carbonate is a basic salt because it is a salt of
- strong acid and strong base
- weak acid and weak base
- strong acid and weak base
- weak acid and strong base
Answer: (d) Weak acid and strong base
Calcium phosphate is present in tooth enamel. Its nature is
Answer: (c) neutral
A sample of soil is mixed with water and allowed to settle. The clear supernatant solution turns the pH paper yellowish-orange. Which of the following would change the colour of this pH paper to greenish-blue?
- Lemon juice
- Common salt
- An antacid
Answer: (d) An antacid
Which of the following gives the correct increasing order of acidic strength?
- Water < Acetic acid < Hydrochloric acid
- Water < Hydrochloric acid < Acetic acid
- Acetic acid < Water < Hydrochloric acid
- Hydrochloric acid < Water < Acetic acid
Answer: (a) Water < Acetic acid < Hydrochloric acid
If a few drops of a concentrated acid accidentally spills over the hand of a student, what should be done?
- Wash the hand with saline solution
- Wash the hand immediately with plenty of water and apply a paste of sodium hydrogencarbonate
- After washing with plenty of water apply solution of sodium hydroxide on the hand
- Neutralise the acid with a strong alkali
Answer: (b) Wash the hand immediately with plenty of water and apply a paste of sodium hydrogen carbonate.
Sodium hydrogencarbonate when added to acetic acid evolves a gas. Which of the following statements are true about the gas evolved?
- It turns lime water milky
- It extinguishes a burning splinter
- It dissolves in a solution of sodium hydroxide
- It has a pungent odour
- (i) and (ii)
- (i), (ii) and (iii)
- (ii), (iii) and (iv)
- (i) and (iv)
Answer: (a) (i) and (ii)
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