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.

When an acid reacts with a base, a neutral salt is formed by the neutralisation process. As neutralisation process is an exothermic reaction, the temperature of the solution increases.

Note:

(i) An acid reacts with a base to form salt and water. This reaction is called the neutralisation reaction. Such a reaction is always exothermic in nature. Hence, the temperature of the solution increases.

(ii) In an exothermic reaction, heat is liberated thereby increasing the temperature.