What functional group is characteristic of carboxylic acids?

Carboxylic acids are characterized by the presence of the -COOH functional group. This group consists of a carbon atom that is double-bonded to an oxygen atom (carbonyl, C=O) and also bonded to a hydroxyl group (-OH). The combination of these two components is what defines a carboxylic acid.

The presence of the -COOH group gives carboxylic acids their acidic properties, as they can donate a proton (H+) to form their conjugate base (the carboxylate ion). This group is what differentiates carboxylic acids from other organic compounds, such as alcohols, aldehydes, and ketones, which are defined by their respective functional groups. The -COOH group is essential in classifying and understanding the behavior of these acids in various chemical reactions.