Why is the `E^(ɵ)` value for the `Mn^(3+)//Mn^(2+)` couple much more position than that for `Cr^(3+)//Cr^(2+)" or "Fe^(3+)//Fe^(2+)` ? Explain.

Explanation

One of the main factors that cotributes to standard potential is ionisation enthalpy. Third ionisation energy of Mn is very high due to the greater stability of `Mn^(2+)` ion . Thus `E_(Mn^(3+)//Mn^(2+))^(0)` value is more positive.