* Solubility: Recrystallization relies on the principle of solubility. The compound you want to purify is dissolved in a hot solvent, and impurities are usually more soluble in the hot solvent too. As the solution cools, the desired compound becomes less soluble and crystallizes out, leaving the impurities behind in the solution.
* Minimizing Dissolution: Warm water would increase the solubility of your crystals, causing some of them to redissolve and be lost in the wash. Cold water minimizes this loss.
* Removing Impurities: Cold water helps to wash away any remaining impurities that might be adhering to the surface of the crystals. The impurities are still more soluble in the cold water than the desired compound.
In summary:
* Cold water minimizes dissolution of the desired crystals.
* Cold water helps to wash away residual impurities.
Let me know if you have any other questions about recrystallization!
