CBSE Class 11-science Answered
In a disproportionation reaction an element in one oxidation state is simultaneously oxidised and reduced. One of
the reacting substances in a disproportionation reaction always contains an element that can exist in at least three
oxidation states. The element in the form of reacting substance is in the intermediate oxidation state; and both higher and lower oxidation states of that element are formed in the reaction.
Example:
2 H2O2 2 H2O + O2
Here, in H2O2, O is in -1 oxidation state , in H2O O is in -2 oxidation state and in O2 O is in 0 oxidation state.
So, oxidation half reaction will be
H2O2 O2
Reduction half reaction will be
H2O2 H2O
Balance now either by half reaction method or oxidation number method.