Hydrofluoric acid, fluohydric acid or hydrogen flouride is a strong acid obtained by the action of concentrated sulphuric acid on fluorspar in a leaden vessel, which, though monobasic, forms double salts of the alkali metals by union of a molecule of salt and of acid. Hydrofluoric acid is a solvent of silica and silicates. Hydrofluoric acid is obtained in aqueous solution by heating calciumfluoride with concentrated sulphuric acid and condensing the gas given off in water.
The anhydrousacid is a colourless liquid, with a boiling-point just above the ordinary temperature. It is usually used in aqueous solution, and is kept in caoutchouc bottles. It blisters the skin and is used for etchingglass. When the vapour is used the etching is transparent, but with the solution it is dull. The glass to be etched is coated with a thin layer of wax, and the design traced with a fine pointed instrument, and after etching the wax is dissolved away and the design becomes visible. Hydrofluoric acid is also used to decompose and dissolve silicates in mineral analysis. Research Hydrofluoric Acid
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
SciTech
Research Hydrofluoric Acid
