Carboxylic acids

Carboxylic acids all contain the carboxyl group (-COOH). When naming carboxylic acids, the same rules as before are followed, but the position of the carboxyl group does not need to be identified, as it is always on C1.

For example, propanoic acid (CH3CH2COOH)

Propanoic acid (C2H5COOH) has structural formula of carbon atom bonded to three hydrogen atoms, joined to carbon with two hydrogens, joined to carbon with hydroxyl group and double-bonded to oxygen.

Carboxylic acids with branches can also be named following the rules.

The longest carbon chain in the molecule below contains four carbon atoms. As the carbon of the carboxyl group is the first of the chain, then both branches are on the third carbon.

3,3-dimethylbutanoic acid has structural formula of carbon atom bonded to three methyl groups, joined to carbon with two hydrogens, joined to carbon with hydroxyl group double-bonded to oxygen atom.

This molecule is therefore called 3,3-dimethylbutanoic acid.