Solubility
Videos
In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution.
Dissolution of sodium chloride in water
Supersaturation
Videos
In physical chemistry, supersaturation occurs with a solution when the concentration of a solute exceeds the concentration specified by the value of solubility at equilibrium. Most commonly the term is applied to a solution of a solid in a liquid, but it can also be applied to liquids and gases dissolved in a liquid. A supersaturated solution is in a metastable state; it may return to equilibrium by separation of the excess of solute from the solution, by dilution of the solution by adding solvent, or by increasing the solubility of the solute in the solvent.
Crystallized sugar (rock candy) is made by adding a seed crystal to a supersaturated solution of table sugar and water. The multiple crystals on the right were grown from a sugar cube, while the left was grown from a single seed taken from the right. A red dye was added to the solution for the left crystal, but was insoluble with the solid sugar, and only traces remain while the rest precipitated out.