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 HA represents the acid, B represents the base, BH represents the conjugate acid of B, and A represents the conjugate base of HA. For example, a Brønsted-Lowry model for the dissociation of hydrochloric acid (HCl) in aqueous solution would be the following: The removal of H from the HCl produces the chloride ion, Cl, the conjugate base of the acid. The addition of H to the HO (acting as a base) forms the hydronium ion, HO, the conjugate acid of the base. Water is amphoteric—that is, it can act as both an acid and a base. The Brønsted-Lowry model explains