Extraction of gold and silver involves leaching the metal with CN^– ion. The metal is recovered by ________________.

Question

Extraction of gold and silver involves leaching the metal with CN – ion. The metal is recovered by ________________.

Philoid · Accepted Answer

4M(s) + 8CN^– (aq)+ 2H₂O(aq) + O₂(g) → 4[M(CN)₂] ^– (aq) + 4OH^– (aq) (M= Ag or Au)

2[M(CN)₂]^-(aq) +Zn(s) →[Zn(CN)₄]^2-(aq) + 2M(s)

Here the metal M(M=Ag or Au) is displaced from the complex by the action of zinc as a reducing agent.

Extraction of gold and silver involves leaching the metal with CN– ion. The metal is recovered by ________________.