In the extraction of silver, zinc metal is used as a reducing agent. What is the molecular structure of the…
In the extraction of silver, zinc metal is used as a reducing agent. What is the molecular structure of the zinc complex formed in this reaction?
Tetrahedral
Linear
Bent
Square planar
Solution
During extraction of silver, the finely powdered silver ore is treated with dilute KCN solution to form a cyano complex of silver. This complex is water soluble.
\(\mathrm{Ag}_2 \mathrm{~S}+4 \mathrm{NaCN} \rightleftharpoons 2 \mathrm{Na}\left[\mathrm{Ag}(\mathrm{CN})_2\right]+\mathrm{Na}_2 \mathrm{~S}\)
Then zinc is added to the solution. More electropositive zinc displaces silver from the complex.
\(\left.2 \mathrm{Na}\left[\mathrm{Ag}(\mathrm{CN})_2\right]+\mathrm{Zn} \longrightarrow \mathrm{Na}_2\left[\mathrm{Zn}(\mathrm{CN})_4\right)+2 \mathrm{Ag}\right]\)
In \(\mathrm{Zn}(\mathrm{CN})_2\), zinc adopts the tetrahedral coordination environment, all linked by bridging cyanide ligands.
Hence, the correct option is (a).