Question

A student prepared 20% sodium hydroxide solution in a beaker containing water. The observations noted by him are given below. (1)
I. Sodium hydroxide is in the form of pellets.
II. It dissolves in water readily.
III. The beaker appears cold when touched from outside.
IV. The red litmus paper turns blue when dipped into the solution.
The correct observations are:
(A) I, II, and III
(B) II, III and IV
(C) III, IV and I
(D) I, II and IV

Answer 1

(D) I, II and IV

Explanation:

Sodium hydroxide is in the form of pellets.

It readily dissolves in water to form a solution.

Sodium hydroxide is an alkali, so it will turn red litmus paper to blue.

These observations are correct.

However, the beaker is not cool to touch. This observation is incorrect.

So option D has all the correct observations listed, I, II and IV. This is the correct option.