What is the process of crystallization primarily used for?

The process of crystallization is primarily used to purify compounds by forming solid crystals. This technique relies on the principle that different substances have different solubilities in a given solvent at certain temperatures. When a saturated solution is cooled or when the solvent evaporates, the solubility limit is exceeded, leading to the formation of solid crystals.

During crystallization, impurities that are present in the solution often remain in the liquid phase and do not crystallize out, which results in a more pure solid product. The well-defined lattice structure of the crystals allows for easier identification and separation of the target compound from undesirable contaminants.

This purification method is commonly employed in various fields, including chemistry, pharmaceuticals, and materials science, where high purity of solid substances is essential for further applications or analyses. Other options do not accurately reflect the central purpose of crystallization; for instance, forming a gas from a liquid phase refers to a different process (vaporization), measuring temperature relates to thermometry, and determining acidity involves techniques such as titration or pH measurement rather than crystallization.