Gold parting of the salt cementation process. This mixture is then added to an earthenware pot and layered with thin sheets of gold fold. The pot is then sealed and heated in a furnace. It was during the medieval period that distillation was discovered and the first description of nitric acid production was given by Pseudo-Geber in the "Summa perfectionis", 1330. Nitric acid is able to dissolve silver. The addition of sal ammoniac to nitric acid creates Aqua regia and this acid is able to dissolve gold. Both acids are used in the acid method of parting but the acids were expensive
Acid–base reaction from an acid produces its "conjugate base", which is the acid with a hydrogen ion removed. The reception of a proton by a base produces its "conjugate acid", which is the base with a hydrogen ion added. Unlike the previous definitions, the Brønsted–Lowry definition does not refer to the formation of salt and solvent, but instead to the formation of "conjugate acids" and "conjugate bases", produced by the transfer of a proton from the acid to the base. In this approach, acids and bases are fundamentally different in behavior from salts, which are seen as electrolytes, subject to the theories