Decomposition Reaction Definition

Iiquids in beakers
In a decomposition reaction, one reactant yields two or more products. Adrianna Williams/Getty Images

A decomposition reaction is a type of chemical reaction in which one reactant yields two or more products.

The general form for a decomposition reaction is:

AB → A + B

Decomposition reactions are also known as analysis reactions or chemical breakdowns. The opposite of this type of reaction is a synthesis, in which simpler reactants combine to form a more complex product.

You can recognize this type of reaction by looking for a single reactant with multiple products.

In certain circumstances, decomposition reactions are undesirable. However, they are intentionally caused and analyzed in mass spectrometry, gravimetric analysis, and thermogravimetric analysis.

Decomposition Reaction Examples

Water can be separated by electrolysis into hydrogen gas and oxygen gas through a decomposition reaction:

2 HAnother example of this type of reaction is the spontaneous decomposition of hydrogen peroxide into water and oxygen:

2 HThe decomposition of potassium chlorate into potassium chloride and oxygen is yet another example:

2 KClO