Question

Name of metal, M which is extracted based on the following equation,

$4\mathrm{M}+8{\mathrm{CN}}^{-}+2{\mathrm{H}}_2\mathrm{O}+{\mathrm{O}}_2\to 4[\mathrm{M}{\left(\mathrm{CN}\right)}_2{]}^{-}+4{\mathrm{OH}}^{-}$

$2[\mathrm{M}{\left(\mathrm{CN}\right)}_2{]}^{-}+\mathrm{Zn}\to {\left[\mathrm{Zn}\right({\mathrm{CN}}_4\left)\right]}^{2-}+2\mathrm{M}$

• A. (a) Cu
• B. (b) Au
• C. (c) Hg
• D. (d) Ni

Answer 1

The correct option is B

(b) Au

Leaching: It is a method of concentrating the ore based upon the differences between the chemical properties of the ore and the gangue.

Cyanide leach mining: cyanide ions bind to the gold and make them to soluble in water.

Extraction of gold: Gold $\left(\mathrm{Au}\right)$ formed in the leaching step is treated with Zinc$\left(\mathrm{Zn}\right)$, then gold is extracted.

So, Gold is extracted by the cyanide process.