The extration of au by leaching with kcn involves oxidation and reduction juscitfy with equation
Answers
Dear student!
The gold is so unreactive, is found as the native metal in free state and not as a compound, so it does not need to be chemically separated. Thus, the gold is leached to get pure metal.
During leaching process, gold (Au) is first oxidized by oxygen of the air to Au+ cation which then combines with CN- ions to form the soluble complex, sodium dicyanoaurate (I).
Gold is then extracted from this complex by displacement method by using a more electropositive zinc metal. In this method, zinc(Zn) acts as a reducing agent and it reduces Au + to Au. Zinc itself gets oxidized to Zn+2 ions which combine with CN- ions to form soluble complex, sodium tetracyanozincate(II).
Thus, extraction of gold by leaching with NaCN involves both oxidation and reduction.