Redox Reactions

In acidic medium, permanganate acts as a strong oxidising agent because of the reaction $8\mathrm{H}^{+}+5e^{-}+\mathrm{MnO}_4^{-}$ → $\mathrm{Mn}^{2+}+4\mathrm{H}_2\mathrm{O}$ Thus, 5 electrons involved in acidic medium reaction. In neutral medium, permanganate acts as a moderate oxidising agent because of the reaction $2\mathrm{H}_2\mathrm{O}+3e^{-}+\mathrm{MnO}_4^{-}$ → $\mathrm{MnO}_2+4\mathrm{OH}^{-}$ Thus, 3 electrons involved in neutral medium reaction. In alkaline medium, potassium permanganate acts in a similar way as in neutral medium. $2\mathrm{H}_2\mathrm{O}+3e^{-}+\mathrm{MnO}_4^{-}$ → $\mathrm{MnO}_2+4\mathrm{OH}^{-}$ Thus, 3 electrons involved in alkaline medium reaction.