Question
Can $\mathrm{Fe}^{3+}$ oxidise $\mathrm{Br}^{-}$to $\mathrm{Br}^2$ at 1 M concentrations?
$\mathrm{E}^{\circ}\left(\mathrm{Fe}^{3+} \mid \mathrm{Fe}^{2+}\right)=0.77 \mathrm{~V}$ and $\mathrm{E}^{\circ}\left(\mathrm{Br} \mid \mathrm{Br}^{-}\right)=1.09 \mathrm{~V}$

Answer

$\mathrm{E}^{\circ}\left(\mathrm{Fe}^{3+} \mid \mathrm{Fe}^{2+}\right)$ is lower than that of $\mathrm{E}^{\circ}\left(\mathrm{Br}^{-} \mid \mathrm{Br}^{-}\right)$.
Therefore, $\mathrm{Fe}^{2+}$ can reduce $\mathrm{Br}^2$ but $\mathrm{Br}^{-}$cannot reduce $\mathrm{Fe}^{3+}$.
Thus, $\mathrm{Fe}^{3+}$ cannot oxidise $\mathrm{Br}^{-}$to $\mathrm{Br}^2$.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free