Electrolysis of molten lead bromide involves oxidation and reduction reaction and hence is a redox reaction. The reactions are as follows :
Reaction at the cathode:
Pb2+ + 2e– ⟶ Pb [Reduction reaction]
Reaction at anode:
Br1- – 1e– ⟶ Br
Br + Br ⟶ Br2 [Oxidation reaction]