 
       
      
    undergoes disproportionation reaction in acidic medium but 
 does not. Give reason.
In , Mn has the highest oxidation state (+7); therefore, it cannot undergo oxidation which is required for disproportionation here. Hence 
 doesn’t undergo disproportionation reaction. Whereas in 
 manganese is in +6 (i.e., less than that of in 
) oxidation state which can be oxidised as well as reduced, hence it undergoes disproportionation.
