Chemistry - Metallurgy Question with Solution | TestHub

Zn being more reactive than Ag and Au, displaces them.

From Native ore,

$\begin{array}{cccc}4\text{Ag}+8\text{NaCN}+2{\text{H}}_2\text{O}+{\text{O}}_2& \stackrel{\text{Leaching}}{\to }& 4\text{Na}\left[\text{Ag}{\left(\text{CN}\right)}_2\right]& + 4\text{NaOH}\\ & & \text{Soluble}& \\ & & \text{Sodium dicyanoargentate (I)}& \end{array}$

$\begin{array}{ccc}2\text{Na}\left[\text{Ag}{\left(\text{CN}\right)}_2\right]+\text{Zn}& \stackrel{\text{Displacement}}{\to }& {\text{Na}}_2\left[\text{Zn}{\left(\text{CN}\right)}_4\right]+2\text{Ag}\downarrow \end{array}$