Qualitative analysis / by William Briggs and R.W. Stewart.

  • William Briggs
Date:
1913
Catalogue details

Licence: Public Domain Mark

Credit: Qualitative analysis / by William Briggs and R.W. Stewart. Source: Wellcome Collection.

    87/180 page 71
    PHOSPHORIC ACID, H3P04. Solution—Sodium Phosphate, Na2HP04. 1. Silver nitrate, AgN03, gives a yellow precipitate of silver phosphate, Ag3P04, soluble in NII4OH and in acids. 3 AgNOg + Na2HP04 = Ag3P04 + 2 NaN08 + HN08. 2. Ammonium chloride, NH4C1, ammonium hydroxide, 3STH4OH, and magnesium sulphate, MgS04 (“ magnesia mixture ”), give a white crystalline precipitate of ammonium magnesium phosphate, NH4MgP04. 2 NH4C1 + NH4OH + MgS04 + Na2HP04 = MgNH4P04 + (NH4)2S04 + 2 NaCl + H20. Precipitation is favoured in dilute solutions by agitation and allowing to stand for a time. 3. Ammonium molybdate, (NH4)2Mo04, gives, on gently warming, a finely divided yellow precipitate in solutions containing excess of nitric acid. The precipitate probably has the composition (NH4)3P04, 12 Mo03. In dilute solutions the liquid becomes yellow, but a precipitate is formed only after gentle warming and standing for some hours. The solution must not be too strong in phosphate. 4. Barium chloride, BaCl2, gives a ivhite precipitate of Ba3(P04)2, soluble in dilute acids. If the solution is neutralized by adding ammonia, Bas(P04)2 is repre- cipitated. 3 BaCl2 + 2 Na2IIP04 = Ba8(P04)2 + 4 KaCl + 2 HOI. Bas(P04)2 + 6 HC1 + 3 BaCl2 + 2 H3 P04. 3 BaCl2 + 2 HsP04 + 6 NH40H = Bas(P04)2 + 6 NH4C1 + C II20. 5. Ferric chloride gives a yellowish-white precipitate of ferric phosphate, FeP04. FeCla + Na2HP04 = FeP04 + 2 KaCl + HC1.
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