Skeleton notes on analytical chemistry : for students in medicine / by Albert J. Bernays.

  • Albert Bernays
Date:
1879
Catalogue details

Licence: Public Domain Mark

Credit: Skeleton notes on analytical chemistry : for students in medicine / by Albert J. Bernays. Source: Wellcome Collection.

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    KI and starcli, blue iodide of starch. FiiKE nitric acid HNO3, i« colorless and caustic in odor; when fuming, yellow from HNOj. Strongly acid, volatile; leaves no residue. HCl pro- duces more or loss of a yellow or orange color, with fumes of chloro-nitric gas NOClj and of Cl„ dissolving Au as AuCls, bleach- ing htmus and indigo-solution. Na^COj effervescence. Stains wool yellow. FeSO, browns : on heating, if dilute. Cu when heated gives 2NO + = 2NO2 as orang(-red vapors. If dilute, neutralize witii CuCOj, filter, evaporate to dryness and decom- pose with H2SO4 containing solution of ferrous sulphate. [PercMorates. HCl added, indigo-solution not bleached. Evolve 0 on iieating, and changed into chlorides : KCl in concentrated sols. pr. KCIO.,.] Eecapitulation. Salts of organic acids, except oxalates, acetates, and formates, are charred when heated. In presence of HCl, soluble carbon- ates, sulphides, hyposulphites, niti ites, ferrocyanides, benzoates, hippurates and urates, chlorates, hypochlorites, and silicates are at once recognizable. Even in admixture a carbonate is decomposed before a sulphite is attacked, so that much is learnt by a careful addition of tlie test. If HCl produces no reaction, the addition of HjS settles the presence or other- wise of chromic acid (p. 53) of As^O^ (p. 14) : boiling, con- centrating and further addition of H„S would indicate by yellow AsjSj + S„, presence of arsenic acid (p. is). Barium chloride BaClj precipitates, in addition to the above-named, iodatcs, bromates, borates, phosphates, oxalates, fluorides, sul- phates, silicotluorides, and ferrocyanides; precipitated BaSO^ and BaFjSiF^ are insoluble in HCl. Silver nitrate precipitates chlorides, bromides, iodides, cyanide.^, and ferricyanides: chlo- ride of barium does not precipitate them. Terric chloride is also an admirable test. The red-brown coloration disappears in the case of acetates, meconates. formates, and the black coloration in the ca^e of the gallates, on addition of HCl, but the brown coloration of ferricyanide and the blood-red sulphocyanide are not thus bleached. HCl, however, in no wise interferes with the FEEROCYANiDE rcactiou. Only in neutral solutions a borate, benzoate and succinate can produce a ferric precipitate, and only in presence of acetic acid, a phosjihate, arsenate and tannate. For further particulars, sen the respective acids, the charac- teristic features of which can be easily mastered by the intelli- gent student. Except for grouping, Tables are not to be recom- mended unless constructed by the student himself.
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