The hydrogen ion is the most abundant in an acid for it is a bare proton that
associates with any water in the molecule, solution or reaction so the H+ ions produced by
an acid exist as H3O+ ions.
Moreover, in the
Arrhenius theory, an acid is a substance that dissociates to produce H+ ions in
solution and a base as a substance that dissociates to produce OH- ions in
solution. Meanwhile, in the
Bronsted-Lowery theory, an acid is considered as a proton donor.
