Through this reaction, iodine is used in redox titrations. Aqueous KI3, "Lugols solution", is used as a disinfectant and as an etchant for gold surfaces.
Air will oxidize iodide, as evidenced by the observation of a purple extract when aged samples of KI are rinsed with dichloromethane. As formed under acidic conditions, hydriodic acid (HI) is a stronger reducing agent.Like other iodide salts, KI forms triiodide (I−3) when combined with elemental iodine.