réactifs

A reagent, or réactif in French, is a substance or compound that is added to a system in order to cause a chemical reaction, or to test if a reaction occurs. Reagents are typically used in laboratories for quantitative or qualitative analysis. They are the substances that are consumed during a chemical reaction. The term "reactant" is often used interchangeably with "reagent," although "reactant" more broadly refers to any substance that participates in a chemical reaction, whether it's added intentionally as a reagent or not.

Reagents are crucial in chemical synthesis and analysis. In synthesis, they are the starting materials that are transformed into desired products. In analysis, reagents are used to detect the presence of specific substances or to measure their quantities. For example, a specific reagent might be used to indicate the presence of a certain ion in a solution by causing a color change. The selection of an appropriate reagent depends on the specific chemical reaction or analysis intended. Factors such as reactivity, selectivity, and solubility are important considerations. Common examples of reagents include acids, bases, oxidizing agents, reducing agents, and indicators. The careful handling and storage of reagents are essential due to their potential reactivity and sometimes hazardous nature.