Aqua regia

Aqua regia was discovered in the 9^th century by the alchemist Jabir ibn Hayyan. It is yellow in colour and has the reputation of dissolving metals like gold.

Aqua regia is obtained by reacting one mole of nitric acid with three moles of hydrochloric acid, the equation for the reaction being:

HNO₃ + 3 HCl → NOCl + 2 Cl + 2 H₂0