Acidified oxidising agents (1 Viewer)

[PeetAbbott]

Why does potassium permanganate KMnO4 become a better oxidising agent when it is acidified? As opposed to being in water, or a basic solution?

 

[CM_Tutor]

Oxidation by permanganate requires the manganese to be reduced. In acidic conditions:

MnO₄^- + 8 H⁺ + 5 e^- ----> Mn²⁺ + 4 H₂O

In neutral / basic conditions, the product is mangaese(IV) oxide rather than manganese(II) ions:

MnO₄^- + 2 H₂O + 3 e^- ----> MnO₂ + 4 OH^-