Answer & explanation:
The decomposition reaction occurs when a compound, by spontaneous (if unstable) or non-spontaneous (if stable) action, when chemically defragmented, generates two new products.
For example:
2AB (s)* → 2A (s) + 2B (g)*
*s is for solid and g for gas
This reaction shows a simple compound AB decomposing into two substances A and B.
What often occurs in decomposition reactions is the formation of a gas (g) and its release after the reaction, due to the fact that the compounds are formed by electron(e⁻) affinity, and gases are extremely electronegative.