Silver halide precipitates. Silver nitrate (AgNO3) was added to three test tubes containing, left to right: potassium chloride (KCl), potassium bromide (KBr) and potassium iodide (KI). Respective silver halides were formed as precipitates. The reactions are: KX + AgNO3 -> AgX + KNO3, where X = Cl, Br, or I. All solutions were 0.5M concentration. These double displacement reactions can be used as a test for presence of halogens in a solution.