Aqua Regia Dissolving Gold

Au + 3HCl + HNO3 → HAuCl4 + NO + 2H2O

Descripción general

Aqua regia (3:1 mixture of HCl and HNO₃) dissolves gold, which is inert to either acid alone. Nitric acid oxidizes gold to Au³⁺ while hydrochloric acid provides chloride ions that stabilize the gold as [AuCl₄]⁻ complex. The synergy between the two acids makes aqua regia effective against noble metals.

Participantes

Rol Sustancia Coeficiente Estado
Reactivo Gold Au 1 (s)
Reactivo Nitric Acid HNO₃ 1 (aq)
Reactivo Hydrochloric Acid HCl 3 (aq)
Producto Water H₂O 2 (l)

Ejemplo cotidiano

During WWII, George de Hevesy dissolved the Nobel Prize gold medals of Max von Laue and James Franck in aqua regia to hide them from the Nazis.

Importancia industrial

El agua regia se utiliza en la refinación del oro, en química analítica para disolver metales nobles y en la recuperación de metales preciosos de residuos electrónicos.

Propiedades

Tipo
Redox
Reversible
No
Energía
Exotérmico
ΔH
-150,0 kJ/mol

Reacciones relacionadas

Iron(II) to Iron(III) Oxidation by Oxygen Bleaching with Sodium Hypochlorite Copper Reduction of Silver Ion Cerium(IV) Reduction by Iron(II) Chlorine Oxidation of Bromide Copper Oxidation by Nitric Acid Hypochlorite Oxidation of Hydrogen Peroxide Hydrogen Peroxide as Oxidizing Agent (Acidic) Zinc Reduction of Silver Ion Displacement of Hydrogen from Acid by Magnesium

Frequently Asked Questions

What is the equation for Aqua Regia Dissolving Gold?
The balanced equation is: Au + 3HCl + HNO₃ → HAuCl₄ + NO + 2H₂O.
What type of reaction is Aqua Regia Dissolving Gold?
Aqua Regia Dissolving Gold is a redox reaction.
Is Aqua Regia Dissolving Gold exothermic or endothermic?
Aqua Regia Dissolving Gold is exothermic (releases energy). The enthalpy change (ΔH) is -150.0 kJ/mol.