Question

A student prepared 20% sodium hydroxide solution in a beaker to study
saponification reaction. Some observations related to this are given below :
(I) The red litmus paper turns blue on dipping in solution.
(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 on dipping in solution.
The correct observations are:
(a) (I), (III) and (IV)
(b) (I), (II) and (III)
(d) Only (I) and (II)
(c) Only (III) and (IV)​

Answer 1

Answer:option 1 is correct

Explanation:

NaOH present in the form of pellets which react with water readily because it is a base. It is basic and hence, turns red litmus paper blue. The beaker when touched should be hot and not cold as the reaction is exothermic and releases heat.

Only the III statement is incorrect. Option A is correct.