Aqua regia, also known as aqua regia, is a highly corrosive liquid with yellow smoke. It is a mixture of nitric acid and hydrochloric acid, in which the mixing ratio is nitric acid: hydrochloric acid = 1:3, and it is also a few substances that can dissolve gold and platinum. This is also the origin of its name. However, some very inert metals such as tantalum will not be corroded by aqua regia. Aqua regia is used in etching process and some analytical processes.

What is aqua regia?

Aqua regia, also known as aqua regia and nitrohydrochloric acid, is a highly corrosive liquid with yellow mist. It is a mixture of concentrated hydrochloric acid and concentrated nitric acid with a volume ratio of 3: 1. It is one of the few liquids that can dissolve gold, and its name comes from its strong corrosiveness.

Aqua regia is generally used in etching process and some detection and analysis processes, but some simple metals such as tantalum, iridium, candles and other higher alkanes, the king of plastics in organic matter-PTFE, silicon and other substances are not corroded by aqua regia, and inorganic salts such as platinum sulfide and barium sulfate are insoluble in aqua regia.

Proportional condition

Both acids are strong acids. One of them is a strongly coordinated acid, which ensures a large number of Cl- and F-. Although it shows stronger metal coordination, it is difficult to completely ionize HF in water and ensure the existence of a large number of F-. Br- is too easy to be oxidized, and it is difficult to ensure strong oxidation of the whole solution. So hydrochloric acid must be used.

The acid must be mild and strong enough, but not too strong. If it is too strong, Cl- will lose the second condition when it is oxidized in large quantities, and concentrated nitric acid just meets this condition in ordinary acid.

Reference to the above content: Baidu Encyclopedia-Wang Shui

What is aqua regia?

Aqua regia is a liquid made of concentrated hydrochloric acid and concentrated nitric acid according to the ratio of 1:3. It has strong solubility, but it cannot dissolve AgCl and BaSO4, but it can dissolve metals such as gold that ordinary acids such as hydrochloric acid and nitric acid cannot dissolve. Therefore, it is called king water.

What is aqua regia?

Aqua regia, also known as aqua regia, is a highly corrosive liquid with yellow smoke. It is a mixture of nitric acid and hydrochloric acid, in which the mixing ratio is 1:3. It is one of the few substances that can dissolve gold and platinum. This is also the origin of its name. However, some very inert metals such as tantalum will not be corroded by aqua regia. Aqua regia is used in etching process and some analytical processes. Aqua regia decomposes quickly and must be prepared directly before use.

One of the royal waters

Aqua regia is a mixture of concentrated nitric acid and concentrated hydrochloric acid. The volume ratio of concentrated nitric acid to concentrated hydrochloric acid is 1∶3.

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

Wang Shuizhi

A colorless liquid consisting of 1 volume of concentrated nitric acid and 3 volumes of concentrated hydrochloric acid. Because it can dissolve other precious metals such as gold and platinum, it was named aqua regia by alchemists. Very corrosive, chlorine-smelling, unstable in nature, and only prepared before use.

Gold and platinum are insoluble in concentrated nitric acid alone, but soluble in aqua regia, mainly because aqua regia contains not only nitric acid, neoecological chlorine, nitrosyl chloride and other oxidants;

Nitric acid+hydrochloric acid = stannous chloride+stannous chloride +2H2O

At the same time, there are high concentrations of chloride ions, which form stable coordination ions with metal ions, such as [AuCl4]-

Belong to the direction of dissolution. The standard electrode potentials of gold and its [AuCl4]- coordination ions are as follows:

Aqua regia and other similar mixed liquids are used in chemical analysis to dissolve some iron ore, phosphate rock, slag, nickel-chromium alloy, antimony and selenium, as well as insoluble sulfides of mercury, arsenic, cobalt and lead.

What is aqua regia in chemistry?

Aqua regia, also known as aqua regia, is a highly corrosive liquid with yellow smoke. It is one of the few substances that can dissolve gold and platinum.

Aqua regia is a mixture of nitric acid and hydrochloric acid, and its mixing ratio is 1:3.

The reaction is nitric acid +3 hydrochloric acid =2H2O+

Cl2+ ion

NOCl