A disproportionation reaction is a special type of redox reaction where the same element in a substance undergoes both oxidation and reduction at the same time.
- In this reaction, one portion of the element’s atoms gets oxidized (its oxidation number increases).
- At the same time, another portion of the same element’s atoms gets reduced (its oxidation number decreases).
- This happens when the element is in an intermediate state, which makes it unstable and able to go in both directions.
Examples in words:
- When hydrogen peroxide breaks down, oxygen atoms in it partly form water (reduced) and partly form oxygen gas (oxidized).
- When chlorine dissolves in water, some chlorine atoms form hydrochloric acid (reduced) while others form hypochlorous acid (oxidized).
In simple words: In a disproportionation reaction, one element “splits roles” – some atoms of it are oxidized while others are reduced at the same time.