Gold dissolves in a aqua-regia forming : — d and f Block Elements Chemistry Question

💡 Solution & Explanation

Step 1: Aqua-regia is a mixture of concentrated hydrochloric acid and concentrated nitric acid in a 3:1 ratio. Step 2: Nitric acid acts as an oxidizing agent that converts gold to gold(III) ions, while hydrochloric acid provides chloride ions to stabilize them as a complex anion. Step 3: The chemical reaction is: Au + HNO3 + 4HCl -> H[AuCl4] + NO + 2H2O. The product H[AuCl4] is chloroauric acid, corresponding to option (c).