Question

When gold and platinum reacts with aqua regia then the species formed respectively are

• A. $AuCl _{3}^{2-}$ and $PtCl _{4}^{2-}$
• B. $AuCl _{4}^{-}$and $PtCl _{6}^{2-}$
• C. $AuCl _{4}^{-}$and $PtCl _{4}^{2-}$
• D. $AuCl _{6}^{3-}$ and $PtCl _{6}^{2-}$

Answer 1

Answer: (B)

$Au +4 H ^{+}+ NO _{3}^{-}+4 Cl ^{-} \longrightarrow AuCl _{4}^{-}+ NO +2 H _{2} O$
$3 Pt +16 H ^{+}+4 NO _{3}^{-}+18 Cl ^{-} \longrightarrow 3 PtCl _{6}^{2-}+4 NO +8 H _{2} O$