Solubility is temperature-dependent; therefore, KDcap K sub cap D only remains constant if the temperature is stable.

The two solvents must not dissolve in one another.

The law states that at a constant temperature, a solute will distribute itself between two immiscible liquids in such a way that the ratio of its concentrations in the two layers is constant, provided the solute exists in the same molecular state in both solvents. Mathematically, this is expressed as:

This is the most common application. It is used to remove a desired substance from a solution by shaking it with a second, immiscible solvent in which the substance is more soluble. This is a staple technique in organic chemistry and pharmaceutical manufacturing.