Question

Why is Bi ( V) a stronger oxidant than Sb (V)?

Answer 1

inert pair effect of bismuth is more prominent than sb so its +3 oxidation state is more stable +5.So bismuth will take up 2 electrons and changeinto bismuth  and bi is an oxidising agent. In case of sb reduction from +5 to +3 will not occur easily.

Answer 2

Explanation:

Oxidation is defined as the process in which an element or atom loses electrons. Whereas atom that undergoes oxidation is known as reductant or reducing agent.

On the other hand, reduction is defined as a process in which an element or atom gain electrons. The atom that undergoes reduction is known as oxidant or oxidizing agent.

For example, $Bi^{+5} + 2e^{-} \rightarrow Bi^{3+}$

Both Sb and Bi are same group elements and as we go down the group then due to inert pair effect there will be increase in +3 oxidation state.

Hence, Bi being the last element easily gains two electrons and reduces to +3 oxidation state from +5.

Therefore, Bi(V) acts as a stronger oxidant than Sb(V).