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Outlines of the course of qualitative analysis followed in the Giessen laboratory / By Henry Will ; With a preface by Baron Liebig.

  • Heinrich Will
Date:
1846
Catalogue details

Licence: Public Domain Mark

Credit: Outlines of the course of qualitative analysis followed in the Giessen laboratory / By Henry Will ; With a preface by Baron Liebig. Source: Wellcome Collection.

    92/152 page 76
    Lime-water does not precipitate malic acid, either in the cold or on boiling. [f. QUINIC ACID.] 2 HO, C, H, O, = 2 HO, Qui. Even very small quantities of this acid may be detected by transforming it into quinone. For this purpose the liquid under examination, concentrated by evaporation, is distilled with half its weight of sulphuric acid and binowxide of manganese. If quinic acid be present, the first portion of the distillate is yellow (shooting into yellow crystals, if a large amount of acid is used), which assumes a blackish-brown colour on being mixed with ammonia. Chlorine water renders it light-green. [g. MECONIC ACID. } 3 H0,C,. HO,, = 3 HO, Me. Salts of sesquowxide of iron impart to solutions of meconic acid or meconates a blood-red colour. Hydrochloric acid precipitates from meconates meconic acid im very slightly soluble crystals, shining like mother o’ pearl. Meconic acid is decomposed by potassa into oxalic acid, car- bonic acid and a dark reddish-brown substance. h. TANNIC ACID. HO, C,, BH, O05 = MO, Gi. This acid is precipitated by mineral acids, in the form of a paste. It is thrown down also by dilute starch-paste, by gelatine and albumen. Tannic acid may be completely withdrawn from its solution by placing into it a piece of animal membrane. Salis of sesquioxide of iron produce in solutions of tannic acid, or tannates, a dark blackish-blue precipitate. The same effect is produced by salts of oxide of tron, but only on exposing the mixture to the air.
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