What is a decomposition reaction?

A decomposition reaction is correctly identified by the characteristic that it involves breaking chemical bonds. In such a reaction, a single compound breaks down into two or more simpler products. This process can often require an input of energy, which might come in the form of heat, light, or electricity, resulting in the breakdown of molecular structures.

The focus on breaking chemical bonds illustrates how reactants can transform into entirely different substances. This type of reaction is fundamental in various processes, including digestion and various industrial applications, where complex molecules are converted into simpler ones for ease of processing or utilization.

Contextually, the other options describe different types of reactions. For example, a reaction that combines two elements to form a compound is characteristic of a synthesis reaction. A reaction that absorbs energy only describes endothermic reactions, which is a broader category and not specifically tied to decomposition. Finally, a reaction that forms a gas from a solid describes a specific scenario that may occur in certain types of reactions but is not defining of decomposition reactions in general.