Acid Base Salt NCERT Exemplar problems mcqs

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?

  1. The temperature of the solution increases.
  2. The temperature of the solution decreases.
  3. The temperature of the solution remains the same.
  4. Salt formation takes place
  1. (i) only
  2. (i) and (iii)
  3. (ii) and (iii)
  4. (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?

  1. Baking powder
  2. Lime
  3. Ammonium hydroxide solution
  4. 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

  1. absorb the evolved gas
  2. moisten the gas
  3. absorb moisture from the gas
  4. 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?

  1. Blue vitriol
  2. Baking soda
  3. Washing soda
  4. Gypsum
    Answer: (b) Baking soda

Sodium carbonate is a basic salt because it is a salt of

  1. strong acid and strong base
  2. weak acid and weak base
  3. strong acid and weak base
  4. weak acid and strong base
    Answer: (d) Weak acid and strong base

Calcium phosphate is present in tooth enamel. Its nature is

  1. basic
  2. acidic
  3. neutral
  4. amphoteric
    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?

  1. Lemon juice
  2. Vinegar
  3. Common salt
  4. An antacid
    Answer: (d) An antacid

Which of the following gives the correct increasing order of acidic strength?

  1. Water < Acetic acid < Hydrochloric acid
  2. Water < Hydrochloric acid < Acetic acid
  3. Acetic acid < Water < Hydrochloric acid
  4. 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?

  1. Wash the hand with saline solution
  2. Wash the hand immediately with plenty of water and apply a paste of sodium hydrogencarbonate
  3. After washing with plenty of water apply solution of sodium hydroxide on the hand
  4. 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?

  1. It turns lime water milky
  2. It extinguishes a burning splinter
  3. It dissolves in a solution of sodium hydroxide
  4. It has a pungent odour
  1. (i) and (ii)
  2. (i), (ii) and (iii)
  3. (ii), (iii) and (iv)
  4. (i) and (iv)
    Answer: (a) (i) and (ii)


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