Water is a polar solvent and like dissolves like, so more polar compound is readily soluble in water
All the alkali halides except lithium fluoride are freely soluble in water. I2 (non-polar) is least soluble in water. Group IIA carbonates (BaCO3) are insoluble in water. PbI2 is sparingly soluble in cold water but quite soluble in hot water. KF (most olar) is most readily soluble in water