The chemical definitions of acids and bases for Arrhenius are:

The chemical definitions of acids and bases for BrØnsted-Lowry are:

Arrhenius defined an acid as a substance that interacts with water to produce excess hydrogen ions in aqueous solution.

A base is a substance which interacts with water to yield excess hydroxide ions, in an aqueous solution according to Arrhenius.

Bronsted-Lowry theory defined an acid as a proton donor while a base is a proton acceptor.