Aqua Regia Apr 2026

Aqua Regia: The "Royal Water" That Dissolves Gold Aqua regia, which means in Latin, is a highly corrosive, fuming liquid. It earned its name from ancient alchemists because it is one of the few substances capable of dissolving "noble" metals like gold and platinum , which typically resist single-acid reactions. Composition and Chemical Reaction

Aqua regia is not a single compound but a freshly prepared mixture of two strong concentrated acids: : 3 parts. Nitric Acid ( HNO3cap H cap N cap O sub 3 ) : 1 part.

: Initially colorless, the mixture quickly turns a vibrant yellow, orange, or red within seconds as the reaction proceeds. aqua regia

: It is exceptionally corrosive and can cause severe chemical burns. Due to the risk of explosions and toxic fumes, laboratories often mandate a "buddy system" and the use of specialized Standard Operating Procedures in a fume hood. Major Industrial Uses

) . These components work together in a two-step process: nitric acid acts as a powerful oxidant to produce tiny amounts of gold ions, while the hydrochloric acid provides chloride ions that react with those gold ions to form stable coordination complexes, effectively pulling the gold into the solution. Physical Properties and Safety Aqua Regia: The "Royal Water" That Dissolves Gold

When these two are combined, they react to form volatile products like and free chlorine ( Cl2cap C l sub 2

: It fumes vigorously and is extremely unstable. Because its active components decompose and escape as gas, it must be prepared immediately before use. Nitric Acid ( HNO3cap H cap N cap O sub 3 ) : 1 part

While it is famous for its history in alchemy, modern industry uses aqua regia for several critical processes: