 Ammonium chloride

Ammonium chloride is the ionic salt $\mathrm{N}{\mathrm{H}}_4\mathrm{Cl}$. In water, its ammonium ion can donate a proton, so the solution's acid-base behaviour is related to the Ammonia-ammonium equilibrium.

This is an example of a salt whose dissolved ions affect pH. Calling a substance a salt describes its ionic composition; it does not imply that every aqueous solution of it must be neutral.