Question

What happens when a solution of an acid is mixed with a solution of a base in a test tube?

(i) The temperature of the solution increases

(ii) The temperature of the solution decreases

(iii) The temperature of the solution remains the same

(iv) Salt formation takes place

• A. (i) only
• B. (i) and (iii)
• C. (ii) and (iii)
• D. (i) and (iv)

Answer 1

The correct option is D

(i) and (iv)

Explanation for correct option:

D.(i) and (iv)

Acid-base reaction:

• When an acid reacts with a base, salt is formed along with water. This reaction is known as the Neutralization reaction.
• Neutralization reactions are highly exothermic in nature. Thus, the temperature of the reaction increases.
• General reaction can be depicted as:

$\mathrm{Acid}+\mathrm{Base}\to \mathrm{Salt}+\mathrm{Water}$

Example of neutralization reaction:

• When Hydrochloric acid reacts with Sodium hydroxide, Sodium chloride is formed along with water.
• The chemical reaction can be depicted as:

$\mathrm{HCl}\left(\mathrm{aq}\right)+\mathrm{NaOH}\left(\mathrm{aq}\right)\to \mathrm{NaCl}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

Explanation for incorrect options:

As option (D) is correct i.e. in an acid-base reaction a salt is formed and since this reaction is exothermic in nature so the temperature will increase. Thus, other options (A), (B) and (C) stand incorrect.

Hence, option (D) i.e. (i) and (iv) is the correct choice.