What is a decomposition reaction?

A decomposition reaction is defined as a chemical process in which a single compound breaks down into two or more simpler substances or elements. This type of reaction is characterized by the breakdown of chemical bonds within the compound, resulting in the formation of new substances.

For example, when water (H₂O) undergoes electrolysis, it decomposes into hydrogen gas (H₂) and oxygen gas (O₂). The key aspect of decomposition reactions is that they involve the transformation of a single reactant into multiple products, highlighting the concept of breaking down complex molecules into simpler forms.

This definition distinguishes decomposition reactions from other types of reactions, such as combination reactions, which involve two or more substances forming a single product, and does not typically account for the energy context or the number of reactants involved that other options might suggest.