Question

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

Answer 1

Nucleophilic addition reaction in aldehydes or ketones

In aldehydes and ketones, the carbonyl group contains a carbon attached to oxygen via a double bond. The carbon acquires a partial positive charge as oxygen is more electronegative. Thus, the carbonyl group is polar, and nucleophiles can easily attack the partial positive charge of carbon. Thus, the reaction is known as nucleophilic addition reaction.


Nucleophilic addition reaction in carboxylic acids

Carboxylic acids contain a carbonyl group, but it does not show nucleophilic addition reactions like aldehyde and ketone. It is due to resonance, as shown below. So, the partial positive charge on the carbonyl carbon atom is reduced.