Hydrogen sulphide, ionization

The eSect of an excess of hydrogen sulphide has very little influence on the solubility of potassium hydrosulphide because, as V. Rothmund has indicated, this salt is too little ionized for the slightly dissociated hydrosulphuric acid to have an appreciable influence on the solubility. 

Zinc sulphide does not precipitate from an acidified solution because the S ion concentration is repressed by the H+ ions of the strong acid, H2S 2H+ + S, and the solubility product of zinc sulphide cannot be reached. Acetate ions, however, remove H+ ions, and, the hydrogen sulphide thus being allowed to ionize to a greater extent, the solubility product of zinc sulphide is exceeded and the white precipitate appears. (See Solubility Product, page 131, and Experiment 22, page 175.)... 

Magnanini studied the absorption spectrum and A. Speransky found that the electrical conductivity of aq. soln. shows that only a small proportion of the salt is ionized. The soln. of the violet modification conducts electricity three times better than that of the green. G. Gore electrolyzed a cone. soln. of chromic fluoride acidified with hydrofluoric and hydrochloric acids, and found that the liquid became hot no gas was liberated at the cathode, but chlorine and ozone were liberated at the platinum anode which was not corroded. C. Poulenc showed that the salt is reduced by hydrogen at dull redness. The heat of formation is 230-95 Cals, per mol—vide infra, the dichloride. Steam transforms chromic fluoride into chromic oxide. Chromic fluoride is insoluble in water, and alcohol hydrogen chloride transforms it into chromic chloride hot hydrochloric, sulphuric, and nitric acids attack chromic fluoride only a little hydrogen sulphide converts it into black sulphide and molten alkali nitrate or carbonate converts it into chromate. A. Costachescu prepared complex pyridine salts. 

The presence of a weak base such as S - or COs " (by bubbling hydrogen sulphide or carbon dioxide through the solution) causes further ionization with precipitation of aluminium hydroxide... 

Hydrogen sulphide is a poor ionizing solvent of low donor properties. It is only very weakly hydrogen bonded in the liquid state and has a low dielectric constant the donor properties are considerably lower than those of water and indeed acceptor properties are also apparent. 

Hydrogen sulphides of the alkali metals, of the ammonium ion and of the tetra-alkylsubstituted ammonium ions act as bases in liquid hydrogen sulphide. The SH ion is comparable in size with the bromide ion the hydrosulphides of sodium, potassium and rubidium are scarcely soluble, but suspensions in liquid hydrogen sulphide can be made to react with acids showing moderate ionization of the dissolved hydrogen sulphides. 

In water hydrogen sulphide is ionized in seawater (pH 7-8) it occurs mainly as HS" ions ... 

---