Copy 1

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.

    113/152 page 97
    ELECTRONEGATIVE BODIKS. oF to the class of acids for which he has to examine. The know- ledge how a salt behaves with solvents, the reaction of the aqueous solutions on vegetable colours, is especially important in this respect. By heating a substance alone or with sulphuric acid, the presence of organic, or volatile inorganic acids may be ascertained. If in both cases we do not observe any of the characteristic phenomena mentioned in p. 82 and 84, the acid is a non-volatile morganic acid, and belongs either to the metallic acids (arsenic acid, antimonic acid [tungstic acid, molybdie acid] chromic acid), to which we have been directed already, when examining for the bases, or it is silicic acid, boracic acid, phosphoric acid, or sul- phuric acid. If we have reason to believe that various acids and their salts are present in the substance under examination, we have to consider the cases in which the preliminary examination in the dry way could give rise to deceptions; for on igniting mix- tures of different salts, or treating them with sulphuric acid, phenomena may be observed, greatly differing from those which every salt would have yielded alone. Compounds of organic acids when mixed with nitrates or chlorates may be ignited without separation of charcoal, a defla- gration, however, generally taking place; in presence of a sufficient quantity of organic matter, nitrates are completely destroyed by ignition, a carbonate beg formed, if the base of the nitrate was an alkali. A mixture of a nitrate and chloride, when treated with sulphuric acid, evolves neither hydrochloric acid nor nitric acid, unless one of them be m great excess, but chlorine and red vapours of nitrous acid. In a mixture of a sulphite and a nitrate, the sulphurous acid is converted into sulphuric acid. Sulphides in presence of sufficient quantities of sulphites, chromate s, chlorates, ete., separate sulphur without disengagement of hydrosulphuric acid ; in most of these cases sulphuric acid is formed. In order not to overlook the presence of volatile organic acids, uncombined with bases, the acid solution is neutralised with carbonate of soda, evaporated and ignited; the organic H
    digitised image 1
    digitised image 2
    digitised image 3