Nitric acid+hydrochloric acid =2H2O+Cl2+NOCl
Aqua regia contains a series of strong oxidants, such as nitric acid, chlorine and nitrosyl chloride, and there are also high concentrations of chloride ions. The oxidation ability of aqua regia is stronger than that of nitric acid. Some metals insoluble in nitric acid, such as gold and platinum, can be dissolved by aqua regia, so aqua regia is called the king of water. The reaction equation of aqua regia dissolving gold and platinum is as follows:
Au+HNO3+4HCl=H[AuCl4]+NO+2H2O
3Pt+4 HNO 3+ 18 HCl = 3 H2[ptcl 6]+4NO+8H2O