Notes on analytical chemistry for students in medicine : extracted from the fifth edition of "Notes for students in chemistry" / by Albert J. Bernays.

  • Albert Bernays
Date:
1889
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Licence: Public Domain Mark

Credit: Notes on analytical chemistry for students in medicine : extracted from the fifth edition of "Notes for students in chemistry" / by Albert J. Bernays. Source: Wellcome Collection.

Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.

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    3 Bad., + Na.,C03 = BaC03 + 2Na01. Sr2N03 + Na^COa = SrC03 + 2NaN03. CaS04 + Na.C03 = CaC03 + Na2SO*4.] /3. To a further portion of the alkaline solution, contained in a test-tube, add Nitrate of Silver AgN03. The precipitate is grey-brown: divided into two portions, the one is soluble without effervescence in Nitric acid, and the other in Ammonia. The solution must contain Hydroxides of Potas- sium, Sodium, Ammonium, Barium, Strontium or Calcium, as these alone are soluble in water. KOH + AgN03 = AgOH + KN03. NaOH + AgN03 = AgOH + NaN03. NH4OH + AgN03 = AgOH + NH4N03. Ba;OH)., + 2AgN03 = 2 AgOH + Ba2N03. Sr(OH).; + 2AgN03 = 2AgOH + Sr2N03. Ca(OH)2 + 2AgN03 = 2AgOH + Ca2N03. All the hydroxides are converted into soluble nitrates, and the Silver nitrate into insoluble grey-brown Silver hydroxide AgOH. If then, in an alkaline solution, Sodium carbonate has produced no ppt., the Alkalies, Potassium, Sodium and Ammonium hy- drates may be present, and their presence is confirmed by the grey-brown ppt. when Silver nitrate has been added. [N.B.— With Amnionic hydrate, Silver nitrate will give no ppt. unless the solution of Ammonia is weak, or the solution of Silver nitrate is strong and in excess, because Silver hydroxide is so soluble in Ammonic hydrate.] Again, if Sodium carbonate has produced a white ppt. in an alkaline solution, the alkaline earths as Hydroxides, respectively, of Barium, Strontium, or Calcium may be present, confirmed by Silver nitrate occasioning a grey-brown ppt. If the ppt. with Silver nitrate in an alkaline solution is liver- brown, readily soluble both in Ammonic hydrate and in Nitric acid, an Arsenate of Potassium, Sodium or Ammonium is pre- sent. Thus, with the common Sodium arsenate: Na.2HAs04 + 3AgN03 = Ag3As04 + 2NaN03 + HN03. If the ppt. is bright yellow, and soluble both in Ammonic hydrate and in Nitric acid, a Phosphate or an Arsenite, of Potas- sium, Sodium or Ammonium is present. E.g. NaJIPO., + 3AgN03 = Ag3P04 + 2NaN03 + HN03. K3As03 + 3AgN03 = Ag3As03 + 3KN03. If the ppt. is paler yellow, a Bromide or an Iodide of Potas- sium, Sodium or Ammonium is present. KBr + AgN03 = AgBr + KN03. KI + AgN03 = Agl + KNO„. a 2