Question

Extraction of gold and silver involves leaching the metal with $C{N}^{-}$ ion. The metal is recovered by ________________.

• A. calcination followed by roasting.
• B. thermal decomposition of metal complex.
• C. displacement of metal by some other metal from the complex ion.
• D. roasting of metal complex.

Answer 1

The correct option is C

displacement of metal by some other metal from the complex ion.

Extraction of gold and silver involves leaching the metal with $C{N}^{-}$ ion. The metal is recovered by displacement of metal by some other metal from the complex ion.

The reactions are involved:

Here, $Zn$ acts as a reducing agent.

So, the correct answer is option (a).