Disproportionation reactions are those in which one element undergoes both oxidation and reduction both simultaneously.
In the reaction,
Oxygen in reactant
H2O2 is in
−1 oxidation state. Oxygen in product
H2O is in
−2 oxidation state and in other product
O2 , it is in 0 oxidation state. So, in this reaction oxygen undergoes oxidation and reductionboth simultaneously.
In the reaction,
Chlorine in reactant
Cl2 is in 0 oxidation state. Chlorine in product
NaCl is in
−l oxidation state and in other product
NaOCl,Na is in
+1 oxidation state, 0 is in
−2 oxidation state and
Cl is in
+1 oxidationstate. So, in this reaction chlorine undergoes oxidation and reduction both simultaneously.