Question

Give balanced chemical equations involved in the extraction of pure silver.

Answer 1

Chemical reactions for leaching: In the first stage, silver reacts with cyanide ions (CN⁻) when water is present. For this reaction, the balanced chemical equation is:

\[\ce{2Ag_{(s)} + 4CN- + 2H2O_{(l)} -> 2(Ag(CN)2)- + 4OH-}\]

Here, silver forms a complex ion (Ag(CN)₂)⁻ in an aqueous solution.

Pure silver can then be recovered by treating the complex ion with zinc. This displacement reaction’s balanced chemical equation is:

Displacement Reaction: Pure silver can then be recovered by treating the complex ion with zinc. This displacement reaction’s balanced chemical equation is:

\[\ce{2(Ag(CN)2)- + Zn_{(s)} -> 2Ag_{(s)} + (Zn(CN)4)^{2-}}\]

Pure silver and a zinc cyanide complex are produced when zinc pushes silver out of the complex in this reaction.