Reciprocal Solubility Influence in Salt Mixtures. the Contributions of Walther Nernst and of Arthur Noyes

In 1887, Walther Hermann Nernst (1864-1941; Nobel Laureate 1920) began his highly successful career as an assistant to Wilhelm Ostwald (1853-1932; Nobel Laureate 1909) at the University of Leipzig. Ostwald strongly supported the ionic theory and had extended it, especially to the dissociation of weak electrolytes. By 1889, Nernst had established the principles of electrode potential, familiarized in the textbook “Nernst equation,” and hence of the emf of a reversible cell. That the solubility of a salt is diminished by the addition of another salt having an ion in common with the first was well known. While briefly at the University of Heidelberg, Nernst developed a quantitative theory of this common ion effect, supported by experiments with uni-univalent strong electrolytes (1).