Question

Which impurities are removed by the following reagents

(b) Lead nitrate solution

Answer 1

Lead Nitrate solution is used to remove hydrogen sulphide$\left({\mathrm{H}}_2\mathrm{S}\right)$.

When Hydrogen sulphide is passed through lead nitrate solution it forms lead sulphide and nitric acid.
$\underset{\mathrm{Hydrogen}\mathrm{sulphide}}{{\mathrm{H}}_2\mathrm{S}\left(\mathrm{g}\right)}+\underset{\mathrm{Lead}\mathrm{nitrate}}{\mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2\left(\mathrm{aq}\right)}\to \underset{\mathrm{Lead}\mathrm{sulphide}}{\mathrm{PbS}\downarrow }+\underset{\mathrm{Nitric}\mathrm{acid}}{2{\mathrm{HNO}}_3}$

Lead Nitrate: Lead nitrate is a colourless white crystalline solid which is soluble in water but insoluble or slightly soluble in alcohol.
It is an oxidizing agent. The chemical formula of Lead nitrate is$\mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2$.