Question

Which is more stable ${\mathrm{PbCl}}_2\mathrm{or}{\mathrm{PbCl}}_4$?

Answer 1

1. Lead is the chemical element with an atomic number $82.$
2. The electronic configuration of Lead is $\left[\mathrm{Xe}\right]4{\mathrm{f}}^{14}5{\mathrm{d}}^{10}6{\mathrm{s}}^{2}6{\mathrm{p}}^2$.
3. The inert pair effect is the tendency of an atom in which two of its outer shell electrons will remain unionized.
4. This term is often used in relation to the increasing oxidation state.
5. As we know that s-orbital electrons are near to the nucleus and are tightly bonded to it.
6. Due to this inert pair effect the higher oxidation state will not be stable as we move down the group.
7. This can be seen in the group $14$ elements as we go down the group the $+2$ oxidation state will become more stable, due to this inert pair effect.
8. This implies that ${\mathrm{Pb}}^{+4}$ is less stable compared with${\mathrm{Pb}}^{+2}$.
9. Hence $+2$oxidation state will get easily reduced, so ${\mathrm{PbCl}}_2$ is much more stable than${\mathrm{PbCl}}_4$.