(D) Gold $(Au)$ is a noble metal and is insoluble in common mineral acids like $HCl$,$H_2SO_4$,or $HNO_3$ individually. It dissolves in aqua regia,whi

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(D) Gold $(Au)$ is a noble metal and is insoluble in common mineral acids like $HCl$,$H_2SO_4$,or $HNO_3$ individually. It dissolves in aqua regia,which is a mixture of concentrated $HCl$ and concentrated $HNO_3$ in a $3:1$ molar ratio. The reaction is: $Au + 4H^+ + NO_3^- + 4Cl^- \rightarrow [AuCl_4]^- + NO + 2H_2O$.