JEE Main 2024 — 8 April, Shift 1 — Question 70

$2 \mathrm{Fe}^{3+}+2 \mathrm{I}^{-} \longrightarrow 2 \mathrm{Fe}^{2+}+\mathrm{I}_{2}$

$2 \mathrm{Fe}^{2+}+\mathrm{S}_{2} \mathrm{O}_{8}{ }^{2-} \longrightarrow 2 \mathrm{Fe}^{3+}+2 \mathrm{SO}_{4}{ }^{2-}$ $\mathrm{Fe}^{+3}$ oxidises $\mathrm{I}^{-}$to $\mathrm{I}_{2}$ and convert itself into $\mathrm{Fe}^{+2}$.

This $\mathrm{Fe}^{+2}$ reduces $\mathrm{S}_{2} \mathrm{O}_{8}{ }^{2-}$ to $\mathrm{SO}_{4}{ }^{2-}$ and converts itself into $\mathrm{Fe}^{+3}$.