Question

Define fractional crystallization.

Answer 1

1. Definition: The process of separating two or more crystalline solids based on the difference in their solubilities in the same solvent is called fractional crystallization.
2. This method is employed in some cases where both or all the constituents of the mixture are soluble in the same solvent but to different degrees.
3. This method is feasible only if the solubility of two crystalline solids, in a particular solvent differs widely.
4. For example, Sodium chloride$\left(\mathrm{NaCl}\right)$, being less soluble, will crystallize first out of a saturated solution of Potassium nitrate$\left({\mathrm{KNO}}_3\right)$ and Sodium chloride.