A chemical reagent is a substance or compound that is used in a chemical reaction to detect, measure, or produce other substances. Reagents can be in various forms, including solids, liquids, or gases, and they play a crucial role in laboratory experiments and industrial processes. They help chemists understand reactions and analyze the properties of different materials. Reagents can be classified into different categories, such as oxidizing agents, reducing agents, and catalysts. Each type serves a specific purpose in facilitating chemical reactions. For example, acids and bases are common reagents used to determine pH levels in solutions, while indicators can signal changes in chemical conditions.