Inhaltsangabe
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated.1898 Excerpt: ... THIRD GROUP. ALUMINIUM, CHKOMIUM, TITANIUM. The oxides and hydroxides of this group are very insoluble in water. The precipitated hydroxides (except metatitanic acid) are easily soluble in acids; but the oxides dissolve with more or less difficulty, and after ignition are almost insoluble. The third-group metals do not form sulphides in the wet way, and for this reason are not precipitated as sulphide by either hydrosulphuric acid (H2S) or alkaline sulphides. Ammonium sulphide precipitates them from neutral solutions as hydroxide. This reaction distinguishes them from the metals of the fourth, fifth, and sixth groups. ALUMINIUM (Al). At. wt. 27.1; sp. gr. 2.58. Aluminium is found in enormous quantities in combination with silica, as clay, feldspar, etc. It also occurs as the oxide and fluoride. It is a moderately hard tin-white metal, very malleable and ductile, and may be highly polished. It fuses at 700 C. It is not oxidized by the air, and is unacted on by hydrosulphuric acid or ammonium sulphide. Nitric acid has scarcely any effect on it, but it is soluble in hydrochloric and sulphuric acids, and in sodium and potassium hydrates: 2A1 + 2KOH-K2A12O4 + 3H2. Aluminium forms the oxide ALOg and a corresponding series of salts. The oxide dissolves with difficulty in dilute acids, but more easily when the acid is concentrated and hot. When fused with sodium or potassium disulphate it is converted into the sulphate, which is easily soluble in water: A1A + 3(K2SO4,SO3) = A12(S04)3 + 3K2SO4. When fused with sodium or potassium hydrate or carbonate (if sodium or potassium hydrate is used the fusion must be made in a silver or nickel crucible) it forms an aluminate soluble in water or acids:-f 2KOH = K2A1204 + H2O. The aluminium salts are almost all colorless. The ...
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