(2) The I2 molecules in iodine are not very soluble in water because they are not opposite in terms of polarity. I2 is non-polar whereas H2O is polar. But when KI is added to water containing iodine, it forms a polar compound i.e. KI3, which is composed of K+ and I3− ions. When the compound becomes polar or ionic, it dissolves in polar solvent i.e. water