Answer:
Option A
Explanation:
Standard electrode potential of reaction [E°] can be calculated as
E0cell=ER−EP
where, ER = SRP of reactant
EP = SRP of product
If E0cell = +ve , then reaction is spontaneous otherwise non-spontaneous
Mn3+ E01=1.51V→ Mn2+
Mn2+ E02=1.181V→ Mn
For Mn2+ disproportionation
E° =-1.51 V - 1.18 v =-2.69 v < 0