What is the characteristic functional group of alcohols?

The characteristic functional group of alcohols is the hydroxyl group, represented as –OH. This functional group is crucial because it defines the chemical behavior and properties of alcohols. The presence of the –OH group enables alcohols to engage in hydrogen bonding, which contributes to their relatively higher boiling points compared to hydrocarbons of similar molecular weight. This also increases their solubility in water, making alcohols important in various biological and chemical processes.

In contrast, the other functional groups listed are associated with different classes of compounds. For instance, –COOH denotes carboxylic acids, which are characterized by the presence of a carboxyl group and exhibit very different reactivity than alcohols. The –NH2 group represents amines, which are characterized by nitrogen-containing structures and also have distinct properties and reactivities. Finally, –CHO signifies aldehydes, which contain a carbonyl group bonded to a hydrogen atom, setting them apart from alcohols. Thus, the presence of the –OH group uniquely identifies compounds as alcohols.