Potassium Bicarbonate

Potassium Iodide is known as Potassium Salt of Hydriodic Acid [HI], available in white crystalline powder form. It is an inorganic compound and has Molecular Formula KI. Its Ionic form is K+ I-, and iodide ion being mild reducing agent, it can be easily oxidized to Iodine by powerful oxidizing agent like chlorine. With elemental iodine it forms I3 (tri iodide), the salts of tri iodide are highly water soluble. On long exposure to air Potassium Iodide becomes yellow due to liberation of Iodine.
Potassium Iodide is more readily soluble in water. The solubility in water increases with the increase in temperature ie. (140 gms. 100 ml @ 20°c, 206 gms 100 ml @ 100°c). It is slightly soluble in ether, ammonia. It absorbs water less readily than Sodium Iodide and hence convenient to use. It is produced industrially by treating Iodine with Potassium Hydroxide. It can also be prepared by the action of Potassium Bicarbonate on Hydriodic acid.
It finds its applications mainly in organic synthesis for the preparation of Aryl iodides [Sandmeyer Reaction] from Aryl amine. Aryl amines are first diazotized by the action of Nitrous acid to obtain Arene diazonium salts which are then iodinated by using Potassium iodide to obtain Aryl Iodide.