Disproportionation Reaction
Definition and meaning of Disproportionation Reaction in chemistry.
A disproportionation reaction is a redox reaction in which a single element simultaneously undergoes both oxidation and reduction, producing two or more products containing that element in different oxidation states.
In more detail
In a disproportionation reaction, one substance acts as both the oxidizing and reducing agent. An element in an intermediate oxidation state is transformed into products where it appears in both higher and lower oxidation states. These reactions are particularly common among halogens, hydrogen peroxide, and certain metal ions in solution. Disproportionation reactions occur spontaneously because the products with separated oxidation states are thermodynamically more stable than the starting material.
Key facts
| Chemical Formula Examples | Cl2, H2O2 |
|---|---|
| Key Characteristic | One element is both oxidized and reduced in the same reaction |
| Field | Inorganic Chemistry |
| Common Systems | Halogens, hydrogen peroxide, metal ions in solution |
A classic example is chlorine gas dissolving in sodium hydroxide solution: Cl2 + 2NaOH → NaCl + NaClO + H2O. Here chlorine transitions from oxidation state 0 to -1 (forming Cl-) and +1 (forming ClO-).
Frequently asked questions
How is disproportionation different from a regular redox reaction?
In typical redox reactions, one substance is oxidized and a different substance is reduced. In disproportionation, the same element undergoes both processes simultaneously within a single reaction.
Why do elements disproportionate?
Disproportionation occurs because the products containing the element in separated oxidation states are thermodynamically more stable than the reactant in its intermediate oxidation state.