JEE Main 2026 — p Block Elements (Group 13 & 14) Question with Solution

The stability of oxidation states in Group 14 is governed by the inert pair effect, which increases down the group.
For Lead ($Pb$), the $+2$ oxidation state is more stable than the $+4$ state ($P{b}^{2+}>P{b}^{4+}$).
In the reaction $Pb{O}_2+Pb\to 2PbO$, $P{b}^{4+}$ is being reduced to $P{b}^{2+}$ and $P{b}^0$ is being oxidized to $P{b}^{2+}$. Since the product contains the more stable oxidation state, the reaction is spontaneous, meaning ${\Delta }_r{G}^{\circ }(1)<0$.
For Tin ($Sn$), the $+4$ oxidation state is more stable than the $+2$ state ($S{n}^{4+}>S{n}^{2+}$).
In the reaction $Sn{O}_2+Sn\to 2SnO$, the stable $S{n}^{4+}$ is being converted into the less stable $S{n}^{2+}$. This process is non-spontaneous, meaning ${\Delta }_r{G}^{\circ }(2)>0$.
Thus, the correct set is ${\Delta }_r{G}^{\circ }(1)<0$ and ${\Delta }_r{G}^{\circ }(2)>0$.