The technique of crystallization is used to separate mixtures where a soluble solid is dissolved in a liquid. It separates solid-liquid mixtures by exploiting differences in solubility. When the solution is concentrated or cooled, the dissolved solid forms pure crystals, leaving impurities in the solution. This method is commonly used to purify solid compounds such as salt from seawater, sugar from syrup, and alum from impure samples. Crystallization is particularly suitable for mixtures where the solid impurities are either insoluble or more soluble than the desired solid, allowing the pure solid crystal to form selectively. It can also separate salts or covalent solids with sufficiently different solubility in a solvent. In summary, crystallization separates solid-liquid mixtures containing a dissolved solid that can be crystallized and purified from impurities in the solution.
