A reagent is a substance or compound that is used in a chemical reaction to bring about a specific transformation or to detect the presence or absence of another substance. Reagents are employed in various laboratory procedures, including chemical analyses, organic synthesis, biochemical assays, and diagnostic tests.
Reagents can be classified into different categories based on their function or role in a reaction:
Reactants: These are substances that are consumed in a chemical reaction to produce new substances. Reactants are typically starting materials that undergo chemical changes to form products.
Catalysts: Catalysts are substances that participate in a chemical reaction without being consumed themselves. They facilitate the reaction by lowering the activation energy required for the reaction to proceed, thereby increasing the reaction rate.
Solvents: Solvents are liquids used to dissolve other substances and create a solution. They provide a medium for chemical reactions to occur by dissolving reactants and facilitating molecular interactions.
Indicators: Indicators are reagents that change color or produce a detectable signal in response to specific chemical conditions. They are often used to monitor the progress of a reaction or to determine the presence or concentration of a particular substance.
Analytical reagents: These are substances used in analytical chemistry to detect, identify, or quantify the presence of specific substances in a sample. Analytical reagents can include reagents for titrations, spectrophotometric assays, chromatography, and other analytical techniques.
Reagents play a crucial role in experimental chemistry and are essential for carrying out controlled chemical reactions, characterizing chemical properties, and elucidating reaction mechanisms. They are carefully selected based on their compatibility with the reaction conditions, their purity, and their ability to achieve the desired outcome.