Hydrochloric acid with metal sulfides

This metallic chloride salt then reacts with the abundant molecules of hydrogen sulfide to produce hydrochloric acid and iron sulfide. 

Properties Lead-gray mineral, subject to blackish tarnish, metallic luster. D 4.52-4.62, Mohs hardness 2. Soluble in concentrated boiling hydrochloric acid with evolution of hydrogen sulfide. 

Amorphous Sb2S2 can be prepared by treating an SbQ solution with 442S or with sodium tliiosulfate, or by heating metallic antimony or antimony trioxide with sulfur. Antimony trisulfide is almost iasoluble ia water but dissolves ia concentrated hydrochloric acid or ia excess caustic. In the absence of air, Sb2S2 dissolves ia alkaline sulfide solutions to form the tliioantimonate(III) ion [43049-98-5], SbS 2, in the presence of air the tetratliioantimonate(V) ion [17638-29-8], SbS , is formed. The lemon-yellow crystalline salt, Na SbS 94420, known as Schhppe s salt [1317-86-8], contains the tetrahedral tetratliioantimonate(V) ion. 

Arsenic pentasulfide (arsenic(V) sulfide), As S q, is stable in air up to 95°C, but at higher temperatures begins to dissociate into arsenous sulfide and sulfur. It is prepared by the fusion of arsenic with sulfur foUowed by extraction with ammonia and reprecipitation at low temperatures by addition of hydrochloric acid. Arsenic pentasulfide is precipitated at low temperatures from strongly acidic arsenate solutions by a rapid stream of hydrogen sulfide. It is hydrolyzed by boiling with water, yielding arsenous acid and sulfur. Salts derived from a number of thioarsenic acids are formed from arsenic pentasulfide and alkaH metal sulfides. 

Hydrochloric acid digestion takes place at elevated temperatures and produces a solution of the mixed chlorides of cesium, aluminum, and other alkah metals separated from the sUiceous residue by filtration. The impure cesium chloride can be purified as cesium chloride double salts such as cesium antimony chloride [14590-08-0] 4CsCl SbCl, cesium iodine chloride [15605 2-2], CS2CI2I, or cesium hexachlorocerate [19153 4-7] Cs2[CeClg] (26). Such salts are recrystaUized and the purified double salts decomposed to cesium chloride by hydrolysis, or precipitated with hydrogen sulfide. Alternatively, solvent extraction of cesium chloride direct from the hydrochloric acid leach Hquor can be used. 

Corrosion products and deposits. All sulfate reducers produce metal sulfides as corrosion products. Sulfide usually lines pits or is entrapped in material just above the pit surface. When freshly corroded surfaces are exposed to hydrochloric acid, the rotten-egg odor of hydrogen sulfide is easily detected. Rapid, spontaneous decomposition of metal sulfides occurs after sample removal, as water vapor in the air adsorbs onto metal surfaces and reacts with the metal sulfide. The metal sulfides are slowly converted to hydrogen sulfide gas, eventually removing all traces of sulfide (Fig. 6.11). Therefore, only freshly corroded surfaces contain appreciable sulfide. More sensitive spot tests using sodium azide are often successful at detecting metal sulfides at very low concentrations on surfaces. 

This 0 -benrylmercaptopropionylglycine (60 g) is dissolved in 400 ml of liquid ammonia, kept at about -50 C, and 12g of sodium metal is gradually added thereto. After the reaction, excess ammonia is removed therefrom, the residue is dissolved in water, washed with ether and the residual aqueous layer is adjusted to pH 1 with hydrochloric acid and concentrated in vacuo in a stream of hydrogen sulfide. The crystalline residue is dried and recrystallired from ethyl acetate to give 25 g of 0 -mercaptopropionylglycine of melting point 95°C to 97°C. 

Cadmium chloride may be prepared by heating the metal with chlorine or hydrogen chloride gas. In the solution, it is formed by treating the metal or its salts, such as oxide, hydroxide, carbonate, or sulfide with hydrochloric acid ... 

Mix 100 g. of granulated aluminum with 90 g. of clean line sand and 90 g. of sulfur. Place the mixture in a fire-clay crucible embedded in sand in a safe place and ignite with fuse powder and a magnesium ribbon, as described in Exercise 85. After the reaction is completed, allow the crucible to cool. Break the crucible, put the contents in an evaporating dish, and treat with water to decompose the aluminum sulfide. This should be done under the hood so that the copious fumes of poisonous H2S will be carried off. Wash away the slimy lumps of melted aluminum from such foreign matter as pieces of crucible. Place these pieces of metal in a beaker, gradually treat with commercial hydrochloric acid until the action has quieted down, then cover with the acid and let stand on the hot plate for several days,... 

The back-extraction (stripping) of palladium is achieved in the hydroxyoxime process by contacting the loaded organic phase with a concentrated solution of hydrochloric acid (about 6 M), thus causing the reversal of reaction (76). Palladium can be recovered from the strip liquor by the addition of ammonia, and the precipitated Pd(NH3)2Cl2 can be calcined to yield pure palladium metal. In the dialkyl sulfide process, however, the extraction reaction (75) is independent of acidity, and is therefore reversed by the use of aqueous ammonia, which forms a stable cationic complex with palladium(II) ... 

Rhenium Sulfides and Selenides.208 209 These catalysts are characterized by their outstanding resistance to poisoning and minimal tendency to cause the hydrogenolysis of carbon-sulfur bonds than the base metal sulfides. Rhenium heptasulfide is easily prepared from boiling 6M hydrochloric acid solutions of perrhenate with hydrogen sulfide. It has been noted that occasional exposure of the dried, powdered catalyst to the atmosphere is not deleterious. 

If the various metals are present in a solution which has been acidified with 6.3 N hydrochloric acid, some of the metal ions precipitate as sulfides and others do not. The metal ions that precipitate as sulfides under these conditions are Hg+-, Cu+, Cd++, Sn++, Sn+ + + +, As+ + +, AS+ + + ++, Sb+ + +, Sb+ + + + -, and Bi+ ++. The solubility products for the corresponding sulfides, HgS, CuS, CdS, PbS, SnS, SnSs, AsgSg, AsoS,v SboSjj, SboS and BigSg, have values corresponding to precipitation under these conditions. These metals are said to constitute the hydrogen sulfide group in the system of qualitative analysis. 

Extraction. — From thorite and thorianite tjie extraction of thoria is easily accomplished. The minerals are easily dissolved in hydrochloric or sulfuric acid (nitric acid may be used for thorianite) and the solution evaporated to expel excess acid and dehydrate the silica. The residue is extracted with water, and the solution saturated with hydrogen sulfide to remove heavy metals. Separation from the rare earth metals may be accomplished by the carbonate, sulfate, or oxalate methods. 

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