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.

    148/180 (page 132)
    (2) Changes which take place when the substance is heated (a) in a closed tube (where the action of air is limited); (ft) in a tube open at both ends, so that the full effect of oxidation may be determined. These experiments will show whether the substance is fusible or readily volatile, and whether it forms an oxide, the nature of which may be also noted, (c) Changes which occur when the substance is heated in presence of reducing agents, such as hydrogen and carbon, and the products obtained under such treatment. (d) The action of water and mineral acids upon the body, and the nature of the products obtained. Examination of liquid substances.—Excluding the gases, which are recognized by the properties described in the text-books, substances may be presented either in the liquid or solid form, or they may be dissolved in water. Some of the well-known gases may also be presented in solution in water, e.g., HC1, IIBr, HI, S02, NH3, etc.; but they may still be recognized by their odour or reactions. The commoner elements or compounds that exist in the liquid state are few, and we shall dispose of them first, and then proceed with the treatment of solids. Of elements there are only two—bromine and mercury : the former a brown liquid, heavier than water, with a marked and characteristic odour; the latter a heavy liquid with a bright silvery lustre. Of compounds there are water, HN03, H2S04, acetic acid, carbon bisulphide, antimony pentachloride (SbCl6), and tin tetrachloride (SnCl4). With the exception of water, sulphuric acid, and carbon bisulphide, these liquids fume in moist air, and the fumes may be rendered more evident by holding a drop of ammonia solution near the liquid. Carbon bisulphide may be distinguished from sulphuric acid or water by its odour, and by being a highly refracting liquid which readily ignites and yields S02 amongst the products of combustion: CSa + 3 02 — C02+ 2 S02.