Electrochemistry 2 Question 30
29. Among the following, identify the correct statement.
(a) Chloride ion is oxidised by $\mathrm{O}_{2}$
(b) $\mathrm{Fe}^{2+}$ is oxidised by iodine
(c) Iodide ion is oxidised by chlorine
(d) $\mathrm{Mn}^{2+}$ is oxidised by chlorine
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Solution:
- For spontaneous redox reaction : $E_{\text {cell }}^{\circ}>0$
For $\quad 2 \mathrm{I}^{-}+\mathrm{Cl}{2} \longrightarrow 2 \mathrm{Cl}^{-}+\mathrm{I}{2}$
$$ E^{\circ}=1.36-0.54=0.82 \mathrm{~V}>0 $$
i.e. $\mathrm{Cl}_{2}$ will spontaneously oxidise $\mathrm{I}^{-}$.
In other cases $E_{\text {cell }}^{\circ}<0$, they are non-spontaneous.
