What is the functional group characteristic of alcohols?

The characteristic functional group of alcohols is the hydroxyl group, represented as -OH. This group consists of a hydrogen atom bonded to an oxygen atom, which is in turn bonded to a carbon atom of an organic molecule. The presence of the hydroxyl group is what defines alcohols and distinguishes them from other types of organic compounds. Alcohols display unique properties such as solubility in water and the ability to form hydrogen bonds due to the -OH group, contributing to their reactivity and behavior in chemical reactions.

The other functional groups mentioned have different characteristics and implications in organic chemistry. The carboxyl group (-COOH) is indicative of carboxylic acids, which have different properties than alcohols. The amino group (-NH2) is found in amines and amino acids, influencing biological functions. Lastly, the carbonyl group (C=O) is a key feature of aldehydes and ketones, affecting their reactivity separately from that of alcohols. Understanding the specific role of the hydroxyl group emphasizes why it is the defining feature of alcohols.