Which functional group is characteristic of alcohols?

The characteristic functional group of alcohols is the hydroxyl group. This group is defined by the presence of a hydroxyl (-OH) moiety, which consists of an oxygen atom bonded to a hydrogen atom. Alcohols are organic compounds that contain one or more hydroxyl groups, and their properties largely stem from the presence of this functional group.

The hydroxyl group is responsible for the polar nature of alcohols, which allows them to form hydrogen bonds with water and other alcohol molecules. This attribute explains why alcohols often have higher boiling points than hydrocarbons of similar molecular weight and why many are soluble in water.

On the other hand, the carbonyl group (found in aldehydes and ketones), amino group (found in amines and amino acids), and carboxyl group (found in carboxylic acids) define different classes of compounds and do not contribute to the defining characteristics of alcohols. Hence, the correct identification of the hydroxyl group as the functional group of alcohols underscores their unique properties and behavior in chemical reactions.