JEE Main 2025 Jan 29 Shift 1, Chemistry Q2: Electrochemical Cell And Nernst Equation

Oxidising strength tracks the standard reduction potential: the more positive $E_{\text{red}}^{\circ }$, the more readily the species accepts electrons, hence the stronger oxidiser.

Among the four couples, ${\mathrm{Pb}}^{4+}/{\mathrm{Pb}}^{2+}$ has the largest positive value $(+1.67\mathrm{V})$, so ${\mathrm{Pb}}^{4+}$ is the strongest oxidising agent in the set.