Double replacement is a type of chemical reaction where two compounds exchange ions or elements to form two new compounds. This process typically occurs in aqueous solutions and involves the formation of a precipitate, gas, or water. The general form of a double replacement reaction can be represented as AB + CD → AD + CB, where A, B, C, and D are ions or molecules. In a double replacement reaction, the driving force is often the formation of an insoluble product, known as a precipitate, or the release of a gas. Common examples include the reaction between sodium chloride and silver nitrate, which produces silver chloride as a precipitate. Understanding double replacement reactions is essential in fields like chemistry and environmental science.