Sodium ammonium chromate sulphate

Ammonium chromate Potassium chromate Chromium potassium sulphate Lithium chromate (yitomium trinitrate Sodium chromate Clsomium fV )oxide Lead chromate Strontium chromate 2nc ctvomate... 

H. M. Dawson and J. McCrae, D. P. Konowaloff, and W. Gaus also used soln. of various salts of the alkali metals, and of potassium, sodium, cupric, or barium hydroxide in place of water and also copper sulphate, copper chloride, zinc sulphate, and cadmium iodide while M. 8. Sherrill and D. E. Russ examined the effect of ammonium chromate. W. Herz and A. Kurzer examined the distribution of ammonia between water and a mixture of amyl alcohol and chloroform. Observations on the distribution of ammonia between water and chloroform were made by T. S. Moore and T. F. Winmill, G. A. Abbott and W. C. Bray, and J. M. Bell. J. H. Hildebrand gave for the molar fraction N X104 of ammonia at 1 atm. press., and 25°, dissolved by ethyl alcohol, 2300 methyl alcohol, 2730 and water, 3300. 

The raw material for this preparation is the chromic anhydride from the preceding preparation, which contains at least a small amount of sodium acid sulphate. This dissolves with the chromic anhydride, and it should remain in the mother liquor (as neutral sulphate) from which the ammonium chromate is crystallized. The second and third crop of crystals of the latter, however, are likely to be contaminated with sodium sulphate. An excess of ammonium hydroxide is used to insure the formation of the neutral chromate. 

If calcium chromate be treated with a soln. of potassium sulphate, the calcium chromate is converted into calcium sulphate, which is precipitated, and potassium chromate, which remains in soln. Instead of leaching the calcium chromate with a soln. of potassium sulphate, W. J. Chrystal showed that if ammonium sulphate is used, a soln. of ammonium chromate is produced, and J. J. Hood found that if the soln. of potassium salt be treated with sodium hydrosulphate, potassium sulphate crystallizes from the soln., while sodium dichromate remains in soln. According to F. M. and D. D. Spence and co-workers, if a mixtiu-e of ammonia and carbon dioxide be passed into the aq. extract of the calcium chromate. Calcium carbonate is precipitated while ammonium and alkali chromate remain in soln. If the liquid be boiled, ammonia is given off, and sodium dichromate remains in soln. S. Pontius used water and carbon dioxide under press, for the leaching ptocess. J. Brock and W. A. Rowell purified alkali chromite by treating the soln. with strontium hydroxide, and digesting the washed precipitate with a soln. of alkali sulphate or carbonate W. J. A. Donald used calcium hydroxide or barium chloride as precipitant. A mixture of chromite with calcium carbonate and potassium carbonate was formerly much employed. Modifications of the process were described by W. J. A. Donald, A. R. Lindblad, C. J. Head, 8. G. Thomas, W. Gow, J. Stevenson and T. Carlile, L. I. Popoff,G. Bessa, P.Weise, P. N. Lukianoff,... 

Discussion. This method is based upon the precipitation of lead chlorofluoride, in which the chlorine is determined by Volhard s method, and from this result the fluorine content can be calculated. The advantages of the method are, the precipitate is granular, settles readily, and is easily filtered the factor for conversion to fluorine is low the procedure is carried out at pH 3.6-5.6, so that substances which might be co-predpitated, such as phosphates, sulphates, chromates, and carbonates, do not interfere. Aluminium must be entirely absent, since even very small quantities cause low results a similar effect is produced by boron ( >0.05 g), ammonium (>0.5 g), and sodium or potassium ( > 10g) in the presence of about 0.1 g of fluoride. Iron must be removed, but zinc is without effect. Silica does not vitiate the method, but causes difficulties in filtration. 

The electrical conductivities of soln. of a great many compounds in liquid hydrogen halides have been measured by E. H. Archibald and D. McIntosh. The conductivity is raised considerably by phosphoryl chloride. Sodium sodium sulphide, borate, phosphate, nitrate, thiosulphate, and arsenate chromic anhydride potassium nitrate, hydroxide, chromate, sulphide, bisulphate, and ferro- and ferri- cyanide ammonium fluoride and carbonate j rubidium and caesium chloride magnesium sulphate calcium fluoride ... 

H. Stamm also measured the solubilities of the salts of the alkalies in liquid ammonia —potassium hydroxide, nitrate, sulphate, chromate, oxalate, perchlorate, persulphate, chloride, bromide, iodide, carbonate, and chlorate rubidium chloride, bromide, and sulphate esesium chloride, iodide, carbonate, and sulphate lithium chloride and sulphate sodium phosphate, phosphite, hypophosphite, fluoride, chloride, iodide, bromate, perchlorate, periodate, hyponitrire, nitrite, nitrate, azide, dithionate, chromate, carbonate, oxalate, benzoate, phtnalate, isophthalate ammonium, chloride, chlorate, bromide, iodide, perchlorate, sulphate, sulphite, chromate, molybdate, nitrate, dithionate, thiosulphate, persulphate, thiocyanate, phosphate, phosphite, hypophosphite, arsenate, arsenite, amidosulphonate, ferrocyanide, carbonate, benzoate, methionate, phenylacetate, picrate, salicylate, phenylpropionate, benzoldisulphonate, benzolsulphonate, phthalate, trimesmate, mellitate, aliphatic dicarboxylates, tartrate, fumarate, and maleinate and phenol. 

Lead acetate solution white precipitate of lead sulphate, PbS04, soluble in hot concentrated sulphuric acid, in solutions of ammonium acetate and of ammonium tartrate (see under Lead, Section III.4, reaction 5), and in sodium hydroxide solution. In the last case sodium tetrahydroxoplumbate(II) is formed, and on acidification with hydrochloric acid, the lead crystallizes out as the chloride. If any of the aqueous solutions of the precipitate are acidified with acetic acid and potassium chromate solution added, yellow lead chromate is precipitated (see under Lead, Section III.4, reaction 6). 

Materials Solutions of calcium, strontium, and barium chlorides, ammonium carbonate, ammonium oxalate, acetic acid, and sodium chromate, calcium sulphate, strontium sulphate. 

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