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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    eacli other constitute what are called salts, and, when freed from the water in which they are dissolved, may often be obtained in crystals. Exp. 19.—Cut a red cabbage into slices, and boil it with water ; strain off the purplish liquid thus obtained. To a portion of this decoction add a little solution of caustic potash : a green liquid will be produced. To another portion of the cabbage liquor add a few drops of sulphuric acid : the solution will become red. Pour the red acid liquor into the green alkaline solution, and stir the mixture : the red colour at first disappears, and the whole remains green ; but on continuing to add the red liquid cautiously, a point is reached at which the liquid assumes a clear blue colour. There is then no excess cither of acid or of alkali in the solution ; and on evaporating the liquid a neutral salt, potassic sulphate, formed by the action of the acid upon the alkali, may be obtained in the form of crystals.* Here it is necessary to remark that the same element often forms more than one oxide which when dissolved in water, furnishes an acid. When this is the case, the oxide which contains the largest quantity of oxygen is designated by a name ending in ic, while the com]rotind with the smaller proportion of oxygen is made to end in pus. Sulphur, for example, furnishes both sulphuric acid (H2S04)and sulphur- ous acid (H2SO3) ; and both these acids form salts when acted •upon by bases. The .salts of acids ending in ic are indicated by names which end in aic, while the salts of acids in pus have names ending in itc. For instance, the salts of sul- phuric acid are called sulphates; of nitric acid, nitrates; of ])hosphoric acid, phosphates; while those of sulphurous * The change may be expressed in .synil)ols in thi.s manner:— Sulphuric Acid Cau.stic I’ot.ash J’ota.ssic Sulph.ate W.itcr 11,504 -h 2KIIO = K,S()4 + 2M4O 2x1+32+16x4 2(39+1 + 16) 2x39 + 32+16x4 2(1x2+16) from which, by reference to tlie table of atomic weights (page 5), it may be .seen that 98 grams of pure sulphuric acid, with 112 grams of caustic potash, would form 174 grams of a neutral salt, and would set free 36 grams of water.