Consider the change in oxidation state of Bromine corresponding to different emf values as shown in the diagram below:Then the species undergoing disproportionation is

Calculate Ecell0  corresponding to each compound undergoing disproportionation reaction.  The reaction for which  Ecell0 comes out to be +ve is spontaneous. HBrO→ Br2; Eº=1.595,SRP(cathode) HBrO→ BrO3−; Eº=−1.5V,SOPAnode 2HBrO→ Br2+BrO3− Ecell0=SRP(cathode)−SRP(Anode)        =1.595−1.5        =0.095V Ecell0>0⇒ΔGº<0(spontaneous)