Carboxylic Acid

Carboxylic acid

Organic compounds containing -COOH as the functional group are called carboxylic acids. The -COOH group is called carboxyl group.

Carboxylic acid

Carboxylic acid

Carboxyl group

Carboxyl group

Classification of Carboxylic Acids

Resonance in Carboxyl Group

The carboxyl group exhibits resonance and has three resonance structures :

Resonance structure of carboxyl group

Although the carboxyl group has three resonance structures, only structures (1) and (3) are considered important because in structures (1) and (3) the carbonyl carbon has complete octet whereas the carbonyl carbon of structure (2) has incomplete octet which makes it less stable.

Nomenclature of Carboxylic Acids

Nomenclature of carboxylic acids is discussed in Nomenclature of carboxylic acids. If you want to learn nomenclature from very basics, refer to Nomenclature Introduction.