Gold with hydrofluoric, hydrochloric, hydrobromic, hydriodic, sulfuric, or nitric acid. It does react with selenic acid, and is dissolved by aqua regia, a 1:3 mixture of nitric acid and hydrochloric acid. Nitric acid oxidizes the metal to +3 ions, but only in minute amounts, typically undetectable in the pure acid because of the chemical equilibrium of the reaction. However, the ions are removed from the equilibrium by hydrochloric acid, forming AuCl ions, or chloroauric acid, thereby enabling further oxidation. Gold is similarly unaffected by most bases. It does not react with aqueous, solid, or molten sodium or potassium hydroxide. It does
Brønsted–Lowry acid–base theory to become its conjugate base, A. The base, B, can accept a proton to become its conjugate acid, HB. Most acid-base reactions are fast so that the components of the reaction are usually in dynamic equilibrium with each other. Consider the following acid–base reaction: Acetic acid, CHCOOH, is an acid because it donates a proton to water (HO) and becomes its conjugate base, the acetate ion (CHCOO). HO is a base because it accepts a proton from CHCOOH and becomes its conjugate acid, the hydronium ion, (HO). The reverse of an acid-base reaction is also an acid-base reaction, between the