Sodium hydrogen arsenates

Na2AsHl5011 sodium hydrogen arsenate heptahydrate 10048-95-0 25.00 1.8700 1 3097 NiBr2 nickel (ii) bromide 13462-88-9 25.00 5.1000 1... 

Sodium hydrogen arsenate Na,HAs03 7778-43-0 186.908 wh powder =195 dec 61 si FtOH... 

Sodium hydrogen arsenate heptahydrate Na3HAs03 7H3O 10048-96-0 312.014 wh monoci cry =50 dec 1.87 61 si FtOH... 

Modem work on arsenical drugs can be said to have started in 1905 it was demonstrated that sodium hydrogen 4-aminophenylarsonate (Atoxyl)... 

Hydrogen fluoride Oxides Sodium nitrate Arsenic trioxide, etc. 

Carbon brings about reduction of arsenious oxide at a temperature below red heat,11 while in carbon monoxide reduction begins at 60° C.12 The numerous reactions of arsenious oxide with organic compounds are described in Vol. XI, Part II, of this Series. Silicon tetrachloride heated for 30 hours at 270° to 280° C. with the oxide yields arsenic trichloride,13 whilst silicochloroform when heated with the oxide in the presence of aqueous sodium hydroxide-or sodium hydrogen carbonate... 

The addition of sodium monohydrogen arsenate to a solution of an aluminium salt results in the precipitation of a white powder which is probably aluminium hydrogen arsenate,5 Al2(HAs04)3. The powder dissolves in acids and the solution in hydrochloric acid when boiled with ammonium sulphite yields a precipitate of aluminium hydroxide, the arsenic remaining in solution. When heated in a current of hydrogen, arsenic is volatilised.6... 

Cadmium Arsenates.—The hydrated normal cadmium orthoarsenate, 2Cd3(As04)2.3H20, falls as a white voluminous precipitate on adding alkali to a solution of cadmium mono- or di-hydrogen arsenate in hydrochloric acid,4 or on addition of sodium orthoarsenate to a solution of cadmium sulphate.5 On drying at 100° C. the anhydrous salt remains. 

The monohvdrate is a dull white insoluble substance which, when treated with aqueous sodium hydrogen carbonate, causes effervescence, a soluble double arsenate being produced. It would appear, therefore, that the hydrated salt is acidic, and determinations of its basicity1 indicate that its formula is Fe0.As02(0H)2. 

Basic mercuric sulphate is converted into mercuric orthoarsenate and mercuric oxide by warming with sodium mono hydrogen arsenate solution. Hot acetic acid will extract the oxide.5... 

Cerium Thioarsenates.—The addition of sodium orthothio-arsenate to an aqueous solution of a cerous salt produces a pale yellow precipitate of cerous orthothioarsenate.1 With sodium hydrogen ortho-thioarsenate the precipitate approximates in composition to cerous pyro-thioarsenate. Ceric salts also give pale yellow precipitates, probably ceric orthothioarsenate. Thioarsenates of other rare earth metals have not been described. 

Separation of arsenic(III) and dimethylarsinic acid by elution with sodium hydrogen carbonate was satisfactory in the pH range 5.2-6.0. Elution of monomethylarsonic acid was accelerated and satisfactory separation from arsenic(V) achieved using saturated aqueous carbon dioxide (pH4.0-4.2) containing lOg L 1 of ammonium chloride. In order to avoid oxidation of trivalent to pentavalent arsenic on the column, it was necessary to pretreat the resin with 1M nitric acid and 0.1M EDTA before use. 

Sodium (+)-arsenyl tartrate, a useful resolving agent,1 is not commercially available. It has been made by the reaction of arsenic(III) oxide with sodium hydrogen (+)-tartrate.2 The following synthesis is an adaptation of this method. 

Arsenic may be determined iodometricaQy. A dried sample of 150-200 mg. is mixed with 7 ml. of 15 N nitric acid and the solution boiled gently for 5-10 minutes. Three milliliters of 2 AT sodium bromate is then added and the mixture evaporated gently to dryness. The residue is taken up in 150 ml. of 4 M hydrochloric acid in an iodine flask then 1 g. of sodium hydrogen carbonate is cautiously mixed in to displace the air, followed by 1 g. of potassium iodide. The flask is then stoppered and allowed to stand 5 minutes. The contents are rapidly titrated with 0.05 N sodium thiosulfate to the disappearance of the iodine color. 

Sodium arsenate (01m). Dissolve 31 2 g disodium hydrogen arsenate hepta-hydrate, Na2HAs04.7H20, in water to which 10 ml concentrated hydrochloric acid was added. Dilute the solution to 1 litre. 

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