Solubilitets

Solubilitets (solubility) is the capacity of a substance to dissolve in a solvent to form a homogeneous solution. It is commonly defined as the maximum amount of solute that can be dissolved in a given amount of solvent at a specified temperature, yielding a saturated solution. Solubility depends on the nature of the solute and solvent and on conditions such as temperature, pressure, and pH.

Solubility is often discussed for solids dissolved in liquids (typical in chemistry and pharmacology), but it also applies to liquids in liquids (miscibility) and gases in liquids. For solids in water, solubility is usually reported as grams of solute per 100 grams of water or as molarity. For gases, solubility typically decreases with increasing temperature and is influenced by pressure (as described by Henry's law).

Solubility can be affected by interactions: similarity in polarity, hydrogen bonding, and ion-dipole attractions between solute and solvent promote dissolution. The presence of other ions can suppress solubility through the common ion effect. The pH can alter solubility for ionizable solutes.

For sparingly soluble salts, solubility is described by the solubility product constant, Ksp, whose value constrains the product of the ion concentrations in solution. Saturated solutions are at equilibrium; supersaturation is a metastable state achieved by rapid cooling or evaporation.

Practical uses include crystallization and recrystallization in purification, formulation of medicines, extraction and separation processes, and environmental assessments of pollutant solubility. Understanding solubility helps predict precipitation, dissolution rates, and bioavailability.