How Can Iodine Achieve Solubility In Water?

The solubility of iodine in water is a fascinating phenomenon rooted in its interaction with iodide ions. On its own, iodine, being a non-polar molecule, is typically insoluble in water. However, when iodine encounters iodide ions in the vicinity of water-chloroform-hexane interfaces, a remarkable transformation occurs. These two elements react to create triiodide ions. Unlike iodine, triiodide ions are soluble in water but not in the non-polar solvent mixture. This unique chemical reaction at the interface between water and the organic solvents allows us to better grasp the intriguing solubility behavior of iodine in water.

The solubility of iodine in an aqueous cetomacrogol solution exhibits a noteworthy temperature-dependent behavior. Within the temperature range of 20 to 50 degrees Celsius, iodine becomes increasingly soluble as the temperature rises. Interestingly, when this solution undergoes cycles of heating and cooling, the cooled solution retains a greater amount of iodine than what could be achieved through equilibration at a constant temperature. This phenomenon suggests that temperature variations have a significant impact on the solubility of iodine in this particular solution, resulting in an accumulation of iodine in the cooled state beyond what one would expect based solely on equilibrium considerations.