Question

A student Prepared 20% sodium hydroxide solution in a beaker to study saponification reaction. Some observations related to this are given below :

(I) Sodium hydroxide solution turns red litmus blue

(II) Sodium hydroxide readily dissolves in water

(III) The beaker containing solution appears cold when touched from outside

(IV) The blue litmus paper turns red when dipped into the solution

The correct observations are :-

(A) I, II and IV

(B) I, II and III

(C) only III and IV

(D) only I and II

Answer 1

Sodium hydroxide is a base. It readily dissolves in water to form an alkaline solution, which turns red litmus paper blue. When sodium hydroxide is dissolved in water, a large amount of heat is evolved, as the process is exothermic in nature. Thus, the beaker containing the sodium hydroxide solution should feel hot when touched from the outside.

Hence, the correct option is D.