Hydrofluoric-acid Sentence Examples
Electrolysis of a solution in hydrofluoric acid gives cobaltic fluoride, CoF3.
Fluorsulphonic acid, SO 2 F OH, is a mobile liquid obtained by the action of an excess of hydrofluoric acid on well-cooled sulphur trioxide.
Balard completed for many years Berzelius's group of " halogen " elements; the remaining member, fluorine, notwithstanding many attempts, remained unisolated until 1886, when Henri Moissan obtained it by the electrolysis of potassium fluoride dissolved in hydrofluoric acid.
Hydrobromic and hydriodic acids were investigated by Gay Lussac and Balard, while hydrofluoric acid received considerable attention at the hands of Gay Lussac, Thenard and Berzelius.
Columbium pentafluoride, CbF5, is obtained when the pentoxide is dissolved in hydrofluoric acid.Advertisement
The salt separates from solutions containing hydrofluoric acid in large plates, which are greenish yellow in colour.
Stannous Fluoride, SnF 2, is obtained as small, white monoclinic tables by evaporating a solution of stannous oxide in hydrofluoric acid in a vacuum.
They pass through a viscous stage in cooling from a state of fluidity; they develop effects of colour when the glass mixtures are fused with certain metallic oxides; they are, when cold, bad conductors both of electricity and heat, they are easily fractured by a blow or shock and show a conchoidal fracture; they are but slightly affected by ordinary solvents, but are readily attacked by hydrofluoric acid.
The surface of the glass had usually been treated with hydrofluoric acid so as to have a satin-like gloss.
Silicofluoric acid, H2SiF6, is obtained as shown above, and also by the action of sulphuric acid on barium silicofluoride, or by absorbing silicon fluoride in aqueous hydrofluoric acid.Advertisement
The anhydrous acid is not known, since on evaporating the aqueous solution it gradually decomposes into silicon fluoride and hydrofluoric acid.
A better method is Wohler's, in which the finely powdered mineral is fused with twice its weight of potassium carbonate in a platinum crucible, the melt powdered and treated in a platinum basin with aqueous hydrofluoric acid.
The filtrate, which may be collected in glass vessels if an excess of hydrofluoric acid has been avoided, deposits the greater part of the salt on cooling.
By dissolving the dioxide in hydrofluoric acid a syrupy solution is obtained which probably contains titanofluoric acid, H 2 TiF 6.
They are obtained by neutralizing the solution of the acid, or by fusing the oxide with potassium carbonate and treating the melt with hydrofluoric acid.Advertisement
Strontium fluoride, SrF 2, is obtained by the action of hydrofluoric acid on the carbonate, or by the addition of potassium fluoride to strontium chloride solution.
Mineral acids generally attack the crystallized metal very little even in the heat; aqua regia, however, dissolves it readily, and so does hydrofluoric acid.
Moissan in 1886 by the electrolysis of pure anhydrous hydrofluoric acid containing dissolved potassium fluoride.
The salts of hydrofluoric acid are known as fluorides and are easily obtained by the action of the acid on metals or their oxides, hydroxides or carbonates.
A characteristic property of the alkaline fluorides is their power of combining with a molecule of hydrofluoric acid and with the fluorides of the more electro-negative elements to form double fluorides, a behaviour not shown by other metallic halides.Advertisement
It forms the acid fluoride KHF 2 when dissolved in aqueous hydrofluoric acid, a salt which at a red heat gives the normal fluoride and hydrofluoric acid.
The fluoride, CrF3, results on passing hydrofluoric acid over the heated chloride, and sublimes in needles.
His work included investigations of osmic acid, of the ferrates, stannates, plumbates, &c., and of ozone, attempts to obtain free fluorine by the electrolysis of fused fluorides, and the discovery of anhydrous hydrofluoric acid and of a series of acides sulphazotes, the precise nature of which long remained a matter of discussion.
In 1886 he succeeded in obtaining the element fluorine in the free state by the electrolysis of potassium fluoride and anhydrous hydrofluoric acid at a low temperature.
Thallous fluoride, T1F, forms white glistening octahedra; it is obtained by crystallizing a solution of the carbonate in hydrofluoric acid.Advertisement
Thorium fluoride, ThF 4, is obtained as a heavy white insoluble powder by dissolving the hydrate in hydrofluoric acid and evaporating.
Potassium thorofluoride, K2ThF6 4H20, is a heavy black powder formed by boiling the hydroxide with potassium fluoride and hydrofluoric acid.
The hexafluoride, WF 6, is a very active gaseous compound, which attacks glass and metals, obtained from tungsten hexachloride and hydrofluoric acid (Ruff and Eisner, Ber., 1905, 38, p. 74 2).
Cupric fluoride, CuF 2, is obtained by dissolving cupric oxide in hydrofluoric acid.
Antimony trifluoride, SbF 3, is obtained by dissolving the trioxide in aqueous hydrofluoric acid or by distilling antimony with mercuric fluoride.
Hydrochloric acid forms a surface film of silver chloride; hydriodic acid readily dissolves it, while hydrofluoric acid is without action.
Silver fluoride, AgF, is obtained as quadratic octahedra, with one molecule of water, by dissolving the oxide or carbonate in hydrofluoric acid.
Ferrous fluoride, FeF21 is obtained as colourless prisms (with 8H2O) by dissolving iron in hydrofluoric acid, or as anhydrous colourless rhombic prisms by heating iron or ferric chloride in dry hydrofluoric acid gas.
Ferric fluoride, FeF 31 is obtained as colourless crystals (with 42H2O) by evaporating a solution of the hydroxide in hydrofluoric acid.
It dissolves slowly in hydrofluoric acid and in nitric acid, the solution turning blue; it is insoluble in hydrochloric acid.
It is insoluble in water and unaffected by most reagents, but when heated in a current of steam or boiled for some time with a caustic alkali, slowly decomposes with evolution of ammonia and the formation of boron trioxide or an alkaline borate; it dissolves slowly in hydrofluoric acid.