The properties of alcohols and phenols are chiefly due to the hydroxyl group, while alkyl and aryl groups modify these properties.

Alcohols and phenols are classified as mono–, di–, tri-, or polyhydric compounds based on whether they contain one, two, three, or many hydroxyl groups, respectively.

Ethers are formed by the substitution of a hydrogen atom in a hydrocarbon by an alkoxy or aryloxy group (R–O/Ar–O).

An example of the application of alcohols is the use of ethanol in ordinary spirit for polishing wooden furniture.

Alcohols and phenols are formed when a hydrogen atom in a hydrocarbon, aliphatic or aromatic, is replaced by an –OH group.