What is the functional group characteristic of carboxylic acids?

The functional group characteristic of carboxylic acids is the carboxyl group, denoted as -COOH. This group is composed of a carbon atom double-bonded to an oxygen atom (carbonyl, C=O) and also bonded to a hydroxyl group (-OH). This unique structure contributes to the properties of carboxylic acids, including their acidity.

The presence of both the carbonyl and hydroxyl components in the carboxyl group allows carboxylic acids to donate a proton (H+) in solution, which is a defining feature of acids. Additionally, the carboxyl group's polarity results in strong intermolecular hydrogen bonding, which significantly impacts the physical properties of carboxylic acids, such as solubility in water and boiling points.

Understanding this functional group is essential because carboxylic acids play crucial roles in biological systems and organic reactions. Their presence in molecules such as amino acids and fatty acids emphasizes their importance in biochemistry and the structure of various organic compounds.