Question

Assertion : Alcohol and carboxylic acid are distinguished by sodium bicarbonate test.
Reason : An aqueous solution of $NaHC{O}_3$ produces brisk effervescence due to the evolution of $C{O}_2$ with a carboxylic acid.
a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
b.) Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c.) Assertion is correct but Reason is incorrect
d.) Both Assertion and Reason are incorrect

Answer 1

Hint: The sodium bicarbonate reacts with a carboxylic acid to produce carbon dioxide gas but with alcohols, the product does not give carbon dioxide. The brisk effervescence is produced when carbon dioxide is evolved.

Complete Solution :
First, let us see what the sodium bicarbonate test is.
- Take a small amount of the compound in the test tube. Then, add to this compound, a small amount of aqueous solution of sodium bicarbonate. The compound will produce brisk effervescence if the carbon dioxide is released by the reaction of sodium bicarbonate with the compound.
- We know that carboxylic acid contains a COOH group. It reacts with sodium bicarbonate to give carbon dioxide but the alcohol has an OH group. It can not give carbon dioxide on reaction with sodium bicarbonate.
- So, it is true that sodium bicarbonate is used to distinguish between carboxylic acid and alcohol.
Thus, the assertion is true.
- Further, the reason is also true and it is the correct explanation of assertion because both compounds are distinguished on basis of the evolution of carbon dioxide gas.
So, the correct answer is “Option A”.

Note: The sodium bicarbonate is the baking soda. It is a white coloured compound used as a cleaning agent. It is also used as an additive during clothes washing. It is used in baking as the leavening agent. It is used in cooking green vegetables because it can give them a bright green colour.