In analytical chemistry, which of the following reactions involves the chemical oxidation of a substance?

The correct answer is combustion, as this reaction involves the chemical oxidation of a substance. In combustion, a fuel reacts with oxygen, leading to the formation of oxides, typically carbon dioxide and water, while releasing energy in the form of heat and light. During this process, the fuel undergoes oxidation as it loses electrons to the oxygen, which serves as the oxidizing agent.

In contrast, reduction refers specifically to the process of gaining electrons, which is the opposite of oxidation. Hydrolysis involves the breaking of chemical bonds through the addition of water, and although it can involve redox reactions, it is primarily considered a reaction involving the alteration of compounds due to water interaction rather than straightforward oxidation. Decomposition involves the breakdown of a compound into simpler substances and does not necessarily imply oxidation unless oxygen is a reactant. Thus, combustion is distinctive for its clear association with the oxidation process.