Question

The $ {\text{P}}{{\text{b}}^{{\text{4 + }}}} $ salts are better oxidizing agents, while $ {\text{G}}{{\text{e}}^{{\text{2 + }}}} $ salts are better reducing agents. Explain.

Answer 1

Hint: Pb and Ge are group 14 elements. Pb that is lead is derived from the Latin word plumbum. Ge that is germanium is the last element to be discovered in group 14. It was discovered by German chemist Clemens Winkler.

Complete step by step solution:
Inert pair effect is the tendency of the two electrons of s-orbital of outermost shell of an element to remain unshared in the compounds of post-transition metals.
Inert pair effect is commonly used to show the relation of increased stability of oxidation states of elements. The term inert pair was first named by Nevil Sidgwick in 1927. The name suggests that the outermost s-electrons are very tightly bound to the nucleus of the atom. Hence, they are difficult to share or ionize.
Therefore, due to inert pair effect,
lead has 82 electrons in total and 4 valence electrons. Two electrons are in p-orbital and two are in s-orbital. Therefore, by inert pair effect lead having 2 electrons in its s-orbital will be more stable than having no electrons in its outermost shell that is lead having $ + 2 $ charge is more stable than $ + 4 $ . Lead has more inert pair effect due to lack of shielding of d and f orbital.
Germanium has 32 electrons in total and 4 valence electrons too, but the shielding effect of germanium is more than lead. Therefore, there is decrease in inert pair effect and that leads to less stability of $ + 2 $ germanium, that means germanium will be less stable if it has 2 valence electrons in its outermost shell and will be more stable if it has no valence electrons. Hence lead gets easily reduced and germanium gets easily oxidised. Therefore, lead is a better oxidizing agent and germanium is a better reducing agent.

Note:
Electrons in an atom shield each other from nuclear pull, this is known as shielding effect. Shielding effect increases the tendency of atoms to lose electrons and form ions. The increasing order of shielding effect is f < d < p < s.