What is the significance of a decomposition reaction?

A decomposition reaction is significant because it fundamentally involves the breakdown of a compound into its individual components, which are often simpler substances or elements. This type of reaction is crucial in various chemical processes and applications, such as in the extraction of metals and in metabolic pathways within living organisms.

For example, when a compound like water (H₂O) undergoes electrolysis, it decomposes into hydrogen gas (H₂) and oxygen gas (O₂). This reaction demonstrates how complex substances can yield more fundamental components, allowing for a better understanding of chemical structure and reactivity.

The other choices describe different types of reactions. The first choice refers to synthesis reactions, where stable compounds are formed from simpler substances. The second option points to combination reactions, where elements combine to form compounds, and the fourth choice describes synthesis or combination reactions where reactive elements come together. These are not pertinent to the definition and significance of a decomposition reaction, which is specifically about breaking down compounds rather than forming them.