Carboxylic acids contain carbonyl group but do not show the nucleophilic addition reaction like aldehydes or ketones. Whey?

Explanation

No doubt, the carboxylic acids contain a carbonyl group but it is a part of carboxyl group and is involved in resonance.

This means that the carbon atom of the carbonyl group is not in a position to accommodate the attacking nucleophile. Therefore, carboxylic acids donot participate in the nuclephilic addition reactions whereas both aldehydes and ketones do participate. For more details, consult section 16.