Introduction to the study of inorganic chemistry / by William Allen Miller.

  • Miller, William Allen, 1817-1870.
Date:
1871
Catalogue details

Licence: Public Domain Mark

Credit: Introduction to the study of inorganic chemistry / by William Allen Miller. Source: Wellcome Collection.

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    Acids a)ui Alkalies. Many elementary substances, like sulphur and phosphorus, by their combination with oxygen, furnish compounds which are freely soluble in water, and have a sour, and often a burning, taste ; they also turn many vegetable blue colours, such as the blue of an infusion of litmus,* or of purple cabbage, to a bright red. Such oxides are called anhytirides (which means bodies free from hydrogen) to distinguish them from the bodies these same oxides furnish when they are acted upon by water, which all contain hydrogen, and belong to the class of acids. All the non metallic elements, except hydrogen and fluorine, form with oxygen one or more compounds, which, when dissolved in water, are acids, and often intensely powerful acids. Many of the metals, on the other hand, by their union with oxygen, give rise to bodies of an opposite kind, which have been termed bases. For instance, the white alkaline substance formed by burning potassium in oxygen is dissolved rapidly by water; it produces a colourless liquid, of a soapy, disagreeable taste, and a peculiar lixivial smell. It corrodes the skin, dis.solves oil-paint, restores the blue colour to litmus which has been reddened by an acid, and ncu/ralises the strongest acids. Tliis power which acids and bases have of uniting with each other, and destroying the chemical activity which each has when separate, is the most marked feature of these two classes of substances. The compounds produced by their action upon * Paper tinged blue with a watery or spirituous infusion of litmus (a colouring matter obtained from certain lichens) is in constant use for showing the presence of an acid in a liquid, as it immediately becomes reddened by the action of even very small quantities of an acid when uncombined with a base. The same paper, if faintly reddened by means of vinegar or any other acid, is er|ually valuable as a h-st for an alkali, which if present uncombined with acids immediately restores the blue colour. The alkalies also turn pa]ier tinged yellow with the colouring matter of turmeric or rhubarb to a reddish-brown hue. h test in chemistry simjily means a method of trial, and lest solutions or test papers, are solutions or jiapers made for the i>ur|>ose of trying whether certain substances are ])resent or not, acoording as the solu- tii)ir or jiaperrloes or does not undergo a particular change, which would Ih produced if the body sought for were there.