A precipitation reaction is a chemical reaction that occurs in an aqueous solution where two ionic bonds combine, resulting in the formation of an insoluble salt called a precipitate. In such reactions, two different soluble salts in aqueous solutions combine to form two products, one of which is insoluble in the solution and is precipitated out. The solid formed is called the precipitate). Precipitation reactions are usually double displacement reactions involving the production of a solid form residue called the precipitate. These reactions occur when cations and anions in aqueous solution combine to form an insoluble ionic solid called a precipitate/Descriptive_Chemistry/Main_Group_Reactions/Reactions_in_Aqueous_Solutions/Precipitation_Reactions). The process of transforming a dissolved substance into an insoluble solid from a supersaturated solution is called precipitation). Precipitation reactions are useful in determining whether a certain element is present in a solution/Descriptive_Chemistry/Main_Group_Reactions/Reactions_in_Aqueous_Solutions/Precipitation_Reactions). They can also be used for making pigments, removing ions from solution in water treatment, and in classical qualitative inorganic analysis).