A Re-Check of Doubtful Points on the Hydrochloric Acid-Solubility Curves of Cadmium and Lead Sulfide

The present investigation is a part of a larger program of study dealing with solubilities and the solubility-product principle in acid solutions.

In particular, this thesis is prepared in an effort to check doubtful points on the unusual solubility curves of cadmium- and lead sulfide in hydrochloric acid solutions of varying normality. The solubility data on these two compounds over a wide range of acid normalities are meager, and the applicability of the solubility-product principle to them, with the possible exception of those in very low acid concentrations, is doubtful.

An investigation of the solubility of cadmium sulf ide has been made recently by Mr. G. F. Kinney, with highly interesting results. These findings indicate that cadmium sul fide does not conform entirely with the solubility product principle. Experiments made by Mr. C. H. Hale show a variance from the solubility product principle for lead sulphide as well as cadmium sulphide, and also show that the solubility curves for these sul f idescross twice in a narrow range of acid normality.

The work instituted in this thesis is an attempt to verify or disprove the peculiar behavior of the sul fides of cadmium and lead, and if possible, suggest a cause for this behavior.