Final answer:
In recrystallization, the dissolution of an impure solid in a hot solvent destroys the impure lattice, allowing for the formation of a purer crystal structure upon cooling. This method leverages the property of increased solubility at higher temperatures to purify substances such as salts.
Step-by-step explanation:
In recrystallization, the dissolution of the impure solid in a suitable hot solvent destroys the impure crystal lattice, and recrystallization from the cold solvent selectively produces a new, more pure crystal lattice. The key to recrystallization is the fact that the solubility of most solids increases with temperature. This means that a compound can be dissolved in a hot solvent at a high concentration but will precipitate as the solution cools because its solubility decreases with temperature. Impurities either remain dissolved or precipitate in a different form, which can then be separated from the desired crystals.
A saturated solution is a solution that contains the maximum amount of solute that is capable of dissolving at a given temperature. When the solution is cooled, it can become supersaturated, which is an unstable state that leads ultimately to the crystallization of the excess solute, leaving any impurities in the solution.
Recrystallization is an effective technique used to purify compounds, often used in synthesizing salts or other chemical substances. By carefully controlling the temperature and choosing the right solvent, the chemist can effectively separate the desired compound from its impurities, leading to a higher purity product.