The functional group present in all alcohols is the

• A. Hydroxyl group
• B. Carboxyl group
• C. Amino group
• D. Carbonyl group

Answer: (A)

Alcohols all share a hydroxyl group, the -OH attached to a carbon skeleton. This -OH group is what defines an alcohol, giving it polarity and the ability to form hydrogen bonds, which influences properties like solubility and boiling point. The carboxyl group (-COOH) is characteristic of carboxylic acids, not all alcohols. The amino group (-NH2) is a feature of amines, and the carbonyl group (C=O) appears in aldehydes and ketones (and carboxylic acids) but not in all alcohols. Therefore, the hydroxyl group is the functional group present in all alcohols.