The hydrogen ion, or hydronium ion, is a Brønsted–Lowry acid when dissolved in HO and the hydroxide ion is a base because of the self-separating reaction
An analogous reaction occurs in liquid ammonia
Thus, the ammonium ion, , in liquid ammonia corresponds to the hydronium ion in water and the amide ion,  in ammonia, to the hydroxide ion in water. Ammonium salts behave as acids, and amides behave as bases.
Some non-aqueous solvents can behave as bases, i.e. accept protons, in relation to Brønsted–Lowry acids.
where S stands for a solvent molecule. The most important of such solvents are dimethylsulfoxide, DMSO, and acetonitrile, , as these solvents have been widely used to measure the acid dissociation constants of carbon-containing molecules. Because DMSO accepts protons more strongly than  the acid becomes stronger in this solvent than in water. Indeed, many molecules behave as acids in non-aqueous solutions but not in aqueous solutions. An extreme case occurs with carbon acids, where a proton is extracted from a  bond.
Some non-aqueous solvents can behave as acids. An acidic solvent will make dissolved substances more basic. For example, the compound  is known as acetic acid since it behaves as an acid in water. However it behaves as a base in liquid hydrogen chloride, a much more acidic solvent.