The Pathway to the Ostwald Dilution Law

The Ostwald Dilution Law, defining the dissociation constant of a weak monobasic acid, or of an analogous base, was announced in 1888. Although this law appears to be simple, the pathway to it was neither straight nor short. Ostwald began his studies of "affinities" (e.g., the relative strengths of acids) at the start of his career. His recognition of the validity of the Arrhenius ionic theory and of the utility of electrolytic conductivity opened the way to further progress. Finally, by use of the van't Hoff extension of the gas laws to the behavior of electrolytes in solution, Ostwald was enabled to achieve his aim.