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

Answer 1

Answer: (A), (B), (D)

The correct options are
A Z is $\left[Zn\right(CN{)}_4{]}^{2-}$
B T is $Zn$
D Q is $O_2$

According to the question,
$Au\underset{H_{2}O}{\overset{C{N}^{-},Q}{\to }}R\stackrel{T}{\to }Au+Z$
The complete reactions are
$Au+2C{N}^{-}+\underset{Q}{O_2}\stackrel{H_{2}O}{\to }\left[Au\right(CN{)}_2{]}^{-}\left(aq\right)+O{H}^{-}$

$\underset{R}{\left[Au\right(CN{)}_2{]}^{-}\left(aq\right)}+\underset{T}{Zn\left(s\right)}\to Au\left(s\right)+\underset{Z}{\left[Zn\right(CN{)}_4{]}^{2-}}$