Hydrogen monosulphide

Hydrogen sulphide 4052 H2S Dlhydrlc sulphide hydrlc sulphide hydrogen monosulphide hydrosulphurlc acid sulphphydrlc acid sulohuret. J hydrogen. 

The oxidation of Cr(III) to Cr(IV) by oxygen dissolved in water is very slow and takes place only in alkaline media. On the other hand, reduction of Cr(VI) in natural waters by bivalent iron is possible especially in acid media and by sulphites and hydrogen monosulphide. The maximum concentration of Cr(VI) in drinking water permitted by the World Health Organization is 0.05 mg. ... 

Sulphides and hydrogen monosulphide at concentrations > 0.05 mg 1 are determined photometrically with iV, iV-dimethyl-p-phenylenediamine. A sensitive and selective determination is based on the production of Methylene Blue during the reaction of hydrogen monosulphide with the above reagent in the presence of Fe ... 

For the determination of higher amounts of hydrogen monosulphide (0.5-20 mg 1 ) and sulphides a iodometric method can be used. In this case sulphides and hydrogen monosulphide are separated in the form of a mixture of insoluble CdS and Cd(OH)2. The precipitate is separated, and known amounts of iodine and HCl are added. Iodine required for oxidation is determined from the difference between the added and remaining quantity of iodine, by titration with thiosulphate [13, 14]. 

J. J. Berzelius melted sulphur with an excess of potassium hydroxide and found the product to be a mixture of the monosulphide and thiosulphate. J. Kircher passed hydrogen sulphide over coarsely powdered sodium hydroxide at 100°. M. J. Fordos and A. Gelis made sodium sulphide by heating sodium carbonate with sulphur to 275° the product is obviously a kind of soda-liver of sulphur. J. W. Kynaston melted sodium hydroxide With calcium sulphide and J. V. Esop, and C. Vincent treated a soln. of barium or other sulphide with sodium or potassium... 

Hence, to prepare a cone. soln. of ammonium monosulphide, a current of washed hydrogen sulphide is passed into cone, aqua ammonia cooled to 0° until the neutral point is reached. Attempts to obtain crystals by cooling the soln. to —40° were not successful. W. P. Bloxam believes that the soln. so obtained is not really the monosulphide at all, but rather a soln. of a mol. of the complex (NH4)2S.2NH4SH in two mols. of ammonium hydroxide, NH4OH because of (i) its action on cupric sulphate (ii) its failure to yield crystals by cooling, attributed to the solvent action of free ammonia and (iii) because it exhibits no tendency to dissolve sulphur. 

Carbon Monosulphide, CS.—This sulphur analogue of carbon monoxide is described as resulting8 on passing carbon disulphide vapour over spongy platinum, pumice stone or red-hot charcoal. It is also formed by the action of the silent electric discharge 7 on carbon disulphide or on a mixture of the latter with either hydrogen or carbon monoxide, thus ... 

The order of stability of the sulphides of vanadium is not the same as that of the oxides for whilst in the oxygen series the penta-com-pound is stable at a red heat, in the sulphur series the penta-compound is converted into tire trisulplride at this temperature. Again, the trioxide is permanent in hydrogen at intense redness, whilst the trisulphide is reduced to the monosulphide under similar conditions. 

From carbon disulphide and hydrogen Hydrogen sulphide and carbon monosulphide ... 

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