Which among $\mathrm{KI}, \mathrm{FeSO}_4, \mathrm{~K}_2 \mathrm{MnO}_4, \mathrm{KMnO}_4$ can't be oxidised…
Which among $\mathrm{KI}, \mathrm{FeSO}_4, \mathrm{~K}_2 \mathrm{MnO}_4, \mathrm{KMnO}_4$ can't be oxidised by $\mathrm{O}_3$ ?
$\mathrm{Kl}$
$\mathrm{FeSO}_4$
$\mathrm{K}_2 \mathrm{MnO}_4$
$\mathrm{KMnO}_4$
Solution
$\mathrm{KMnO}_4$ is not oxidised by $\mathrm{O}_3$ because $\mathrm{KMnO}_4$ produces $\mathrm{MnO}_4^{-}$ion, the $\mathrm{Mn}$ in this $\mathrm{MnO}_4^{-}$ion is in +VII oxidation state which is maximum for Mn. So, it cannot be further oxidised. Hence, the correct option is (4).