Question

The cyanide process of gold extraction involves leaching out gold from its ore with $C{N}^{-}$ in the presence of $Q$ in water to form $R$. Subsequently, $R$ is treated with $T$ to obtain $Au$ and $Z$. Choose the correct option(s)

• A. Q is $O_2$
• B. T is Zn
• C. Z is $[Zn(CN{)}_4{]}^{2-}$
• D. R is $[Au(CN{)}_4{]}^{-}$

Answer 1

Answer: (A), (B), (C)

$4Au(s)+8C{N}^{-}(aq)+2H_{2}O(aq)+\underset{\text{(Q)}}{O_{2(g)}}\to 4[Au(CN{)}_2{]}^{-}(aq)+4O{H}^{-}(aq)$
$\underset{\text{(R)}}{2[Au(CN{)}_2{]}^{-}}(aq)+\underset{\text{(T)}}{Zn(s)}\underset{\text{(Z)}}{\to [Zn(CN{)}_4{]}^{2-}}(aq)+2Au(s)$