Among the following, which is the strongest oxidizing agent?

Concept: $E°_{M^{3+}/M^{2+}}$ — higher value = stronger oxidising agent

| Ion | $E°_{M^{3+}/M^{2+}}$ (V) | Reason | |-----|--------------------------|--------| | $\text{Mn}^{3+}$ | $+1.57$ | Product $\text{Mn}^{2+}$ ($3d^5$, half-filled) is extra stable | | $\text{Fe}^{3+}$ | $+0.77$ | Moderate | | $\text{Ti}^{3+}$ | $-0.37$ | Poor oxidiser | | $\text{Cr}^{3+}$ | $-0.41$ | $\text{Cr}^{3+}$ ($3d^3$) is very stable, poor oxidiser |

$\text{Mn}^{3+}$ is the strongest oxidising agent because $\text{Mn}^{2+}$ (the reduction product) has the extra-stable half-filled $3d^5$ configuration.

Answer: Option (1) — $\text{Mn}^{3+}$