Nitrohydrochloric acid

Nitrohydrochloric acid is a highly corrosive, strong acid, also known as Aqua regia. It is a mixture of nitric acid and hydrochloric acid, typically in a molar ratio of 1:3. Nitrohydrochloric acid was named by alchemists who used the substance to dissolve noble metals such as gold and platinum, which could not be dissolved by any single acid alone.

History

The acid was known to the Alchemists as 'Aqua regia', or 'royal water', due to its ability to dissolve the so-called royal metals, gold and platinum. Its preparation was a closely guarded secret among the alchemists.

Preparation

Nitrohydrochloric acid is prepared by slowly adding concentrated nitric acid to an equal volume of concentrated hydrochloric acid while stirring. The resulting reaction produces a fuming, reddish-brown solution. The reaction is exothermic and releases a large amount of heat, which can lead to boiling and splattering if not controlled.

Uses

Nitrohydrochloric acid has several uses in the industry and in the laboratory. It is primarily used to dissolve noble metals such as gold and platinum, which are resistant to most other acids. It is also used in some analytical chemistry applications for the digestion of samples.

Safety

Due to its highly corrosive nature, nitrohydrochloric acid should be handled with care. It can cause severe burns and eye damage, and its fumes are harmful if inhaled.

See also

• Acid
• Aqua regia
• Nitric acid
• Hydrochloric acid