Aqua Regia Dissolving Gold

Au + 3HCl + HNO3 → HAuCl4 + NO + 2H2O

Visão geral

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

Papel Substância Coeficiente Estado
Reagente Gold Au 1 (s)
Reagente Nitric Acid HNO₃ 1 (aq)
Reagente Hydrochloric Acid HCl 3 (aq)
Produto Water H₂O 2 (l)

Exemplo do 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.

Importância industrial

A água-régia é utilizada na refinação de ouro, em química analítica para dissolver metais nobres e na recuperação de metais preciosos a partir de resíduos eletrónicos.

Propriedades

Tipo
Redox
Reversível
Não
Energia
Exotérmico
ΔH
-150,0 kJ/mol

Reações relacionadas

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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.