Magnesia mixture

Phosphates and Arsenates. — Dissolve 5 gm. of ammonium sulphate in 20 re. of water, and add to the dear solution 3 e.c. of magnesia mixture and 10 cc. of ammonia water. No precipitate should form on standing twelve hours. 

Phosphoric Acid. — Concentrate 5 cc. of hydrogen peroxide on the water-bath, take up any residue with 3 cc. of water, add 1 cc. of magnesia mixture and 3 cc. of ammonia water. No precipitation should take place on standing twelve hours. 

Rhombic ny.sl.als. or white crystalline powder, easily soluble iti water. Its principal asc is in the preparation of magnesia mixture, for the determination of phosphoric acid. 

Magnesium Tetrarsenite, Mg3As409.wH20, is formed when a solution of magnesium sulphate or magnesia mixture is added to an aqueous solution of arsenious oxide.12... 

To detect an arsenite and an arsenate in the presence of each other, the neutral solution should be treated with ammonia and magnesia mixture. The precipitate, treated with Bettendorff s reagent, gives a black precipitate of arsenic, indicating arsenate the filtrate, acidified with hydrochloric acid and treated with hydrogen sulphide, yields a precipitate of arsenious sulphide, indicating arsenite.6... 

Gabis, V. and Graba, L., Microstructure of reaction-sintered spinel/corundum refractories prepared from various alumina-magnesia mixtures , Euro. Ceramics., 1991 2593-8. 

An example of dispersion of sound in an air-magnesia mixture with solid-to-air mass ratio, mp, of 0.3 for pp/p (=f) of 100 and 1,000 is illustrated in Fig. 6.10 [Soo, I960]. The figure gives the dispersion of sound for various values of N when the heat transfer is neglected. Under the same experimental condition, the relationship between pag/co and Na, is shown in Fig. 6.11 [Soo, I960]. It is noted that the preceding model is valid only... 

Figure 6.10. Dispersion of acoustic waves in the air-magnesia mixture (from Soo, 1960).

Magnesium nitrate reagent or magnesia mixture White crystalline precipitate of magnesium ammonium phosphate soluble in acetic acid and mineral acids practically insoluble in 2.5% ammonia solution... 

Magnesia mixture or magnesium reagent Cadmium acetate and dilute acetic acid Zinc sulfate White precipitate soluble in excess reagent but reprecipitated on boiling White precipitate White precipitate insoluble in dilute acetic acid soluble in dilute ammonia solution, yielding a white precipitate on boiling... 

The precipitates obtained with magnesia mixture (magnesium chloride in ammoniacal solution), or ferric chloride in an acid solution to which sodium acetate has been added, are often used as tests for phosphate (see p. 180), and in the latter case the phosphate is removed from solution as ferric phosphate. Another common test is the formation of yellow ammonium phosphomolybdate when, a nitric acid solution of ammonium molybdate is added to phosphate solution (see pp. 180, 181). 

Identification Dissolve 1 g of sample in 5 mL of 1 2 hydrochloric acid, and add an excess of 1 A sodium hydroxide. A red-brown precipitate forms. Boil the mixture, filter to remove the iron, and strongly acidify a portion of the filtrate with hydrochloric acid. Cool, mix with an equal volume of magnesia mixture TS, and treat with a slight excess of 6 A ammonium oxide. An abundant white precipitate forms. This precipitate, after being washed, turns green-yellow when treated with a few drops of silver nitrate TS. 

Magnesia Mixture TS Dissolve 5.5 g of magnesium chloride (MgCl2-6H20) and 7 g of ammonium chloride (NH4CI) in 65 mL of water, add 35 mL of 6 IV ammonium hydroxide, set the mixture aside for a few days in a well-stoppered bottle, and filter. If the solution is not perfectly clear, filter it before using. 

Magnesia mixture (a solution containing MgCl2, NHACl, and a little NH3) no precipitate (distinction from arsenate). 

Magnesia mixture (see Section III.12, reaction 3) white, crystalline precipitate of magnesium ammonium arsenate Mg(NH4)As04.6HzO from neutral or ammoniacal solution (distinction from arsenite) ... 

Table VI.10 Separation of As03, As04, and P04 Dilute 5 drops of the soda extract with an equal volume of water, acidify with dilute HC1 and render alkaline with dilute NH3 solution. Centrifuge, if necessary, and discard the ppt. Treat the clear solution with 10-12 drops of Mg(N03)2 reagent (or of magnesia mixture) added dropwise and with stirring. Allow to stand for 10 minutes, stirring frequently centrifuge. Wash the ppt. with 2-3 drops dilute NH3 solution.

May contain As, Au, Mo, Se, and Te as chlorides or acids. Render alkaline with ammonia solution, add Mg(N03)2 reagent or magnesia mixture, allow to stand for 5 minutes with frequent stirring or shaking. Filter. 

Magnesia mixture (0 5m for magnesium). Dissolve 102 g magnesium chloride hexahydrate, MgCl2.6H20, and 107 g ammonium chloride, NH4C1, in water, dilute to 500 ml, add 50 ml concentrated ammonia and dilute the solution to 1 litre with water. 

The solution is then diluted with 100 ml. water, treated with about 5 ml. of a saturated solution of acid sodium ammonium phosphate and then an excess (about 40 ml.) of magnesia mixture added. A precipitate forms and is dissolved in dilute nitric add the solution is then heated to boiling, an excess of ammonia added, and it is then allowed to stand for about 2 hours. The precipitate is filtered off, washed with dilute ammonia and dissolved in 70 ml. dilute hydrochloric acid (3 2). 

The acid is isolated from the reaction mixture in the form of its magnesium salt by the aid of magnesia mixture, the free acid being obtained by adding the requisite amount of sulphuric acid. The yield of magnesium salt by this process is 42 per cent., and it forms pearly white, soapy crystals, containing half a molecule of water of crystallisation. 

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