supersaturace

Supersaturace refers to a state where a solution contains more dissolved solute than it theoretically can at a given temperature and pressure. This is an unstable condition, often achieved by carefully cooling a saturated solution without disturbing it. In a supersaturated solution, the excess solute is not precipitating out, despite the thermodynamic driving force for it to do so.

This state is metastable, meaning it can persist for some time but is easily disrupted. Introducing a seed crystal of the solute, a tiny scratch on the container, or even a significant jolt can trigger rapid crystallization. This process, known as nucleation, allows the excess solute to precipitate out of the solution until it reaches saturation.

Supersaturation is a common phenomenon in various applications. It is utilized in the formation of crystals in industries like sugar refining and salt production. It also plays a role in phenomena such as the formation of fog or clouds when water vapor cools and becomes supersaturated with respect to liquid water or ice. The careful control of supersaturation is crucial for achieving desired crystal sizes and purity in many chemical processes. The reverse process, where a solution is unsaturated and can dissolve more solute, is much more stable.