JEE Main 2025 Apr 7 Shift 1, Chemistry Q13: Group 14 Elements: The Carbon Family

The two lowest first ionisation enthalpies in group 14 belong to the heaviest stable members, tin and lead. So A = Sn and B = Pb.

The inert pair effect makes the $+2$ oxidation state increasingly stable down group 14 and the $+4$ state increasingly unstable.

• Sn${}^{2+}$: less stable than Sn${}^{4+}$ $\Rightarrow$ Sn${}^{2+}$ tends to lose two more electrons and gets oxidised, so it acts as a reducing agent.
• Pb${}^{4+}$: less stable than Pb${}^{2+}$ $\Rightarrow$ Pb${}^{4+}$ tends to accept electrons and gets reduced, so it acts as an oxidising agent.

$\therefore$ A${}^{2+}$ is reducing and B${}^{4+}$ is oxidising $\Rightarrow$ Option (3).