Of the hygroscopic substances in common use, phosphoric anhydride, concentrated sulphuric acid, and dry potassium hydrate are almost equal in power; sodium hydrate and calcium chloride are not much behind.
The hydrated salt readily loses water on heating, forming at 100° C. the hydrate CoBr 2.2H 2 O, and at 130° C. passing into the anhydrous form.
GOTHITE, or Goethite, a mineral composed of an iron hydrate, Fe203.H20, crystallizing in the orthorhombic system and isomorphous with diaspore and manganite.
Chim., 1906, 2 5, p. 2 53) considers to be a hydrate of sulphur of composition S $ H 2 0), sulphuric acid, traces of trithionic acid, tetraand pentathionic acids and probably hexathionic acid.
Chem., 1905, (2), 71, p. 452) by reducing ruthenium salts with hydrazine hydrate in the presence of gum-arabic.
This view was modified by Liebig, who regarded ether as ethyl oxide, and alcohol as the hydrate of ethyl oxide; here, however, he was in error, for he attributed to alcohol a molecular weight double its true value.
Filter from the bismuth hydrate, and if copper is present, add potassium cyanide till the colour is destroyed, then pass sulphuretted hydrogen, and cadmium is precipitated as the yellow sulphide.
A standard sodium hydrate solution can be prepared by dissolving 42 grammes of sodium hydrate, making up to a litre, and diluting until one cubic centimetre is exactly equivalent to one cubic centimetre of the sulphuric acid.
Where a solution is likely to change in composition on keeping, such as potassium permanganate, iodine, sodium hydrate, &c., it is necessary to check or re-standardize it periodically.
Chloraloxime, CC1 3 CH: NOH, is obtained when one molecular proportion of chloral hydrate is warmed with four molecular proportions of hydroxylamine hydrochloride and a little water.
It crystallizes in prisms which melt at 39° C. A chloral hydroxylamine, CC1 3 [[Choh Nhoh]], melting at 98° C. is obtained by allowing a mixture of one molecular proportion of chloral hydrate with two molecular proportions of hydroxylamine hydrochloride and one of sodium carbonate to stand for some time in a desiccator.
If a glucose solution be added to copper sulphate and much alkali added, a yellowish-red precipitate of cuprous hydrate separates, slowly in the cold, but immediately when the liquid is heated; this precipitate rapidly turns red owing to the formation of cuprous oxide.
Water when absolutely pure has no action on lead, but in the presence of air the lead is quickly attacked, with formation of the hydrate, Pb(OH) 2, which is appreciably soluble in water forming an alkaline liquid.
The corresponding hydrate, Pb(OH)2, is obtained as a white crystalline precipitate by adding ammonia to a solution of lead nitrate or acetate.
Uranous hydrate is obtained as reddish-brown flakes by precipitating a uranous solution with alkali.
The chloride readily combines with water to form a crystallizable hydrate SnCl 2.2H 2 O, known as "tin salt" or "tin crystals."
Water, at ordinary or slightly elevated temperatures, is decomposed more or less readily, with evolution of hydrogen gas and formation of a basic hydrate, by (I) potassium (formation of KHO), sodium (NaHO), lithium (LiOH), barium, strontium, calcium (BaH 2 O 2, &c.); (2) magnesium, zinc, manganese (MgO 2 H 2, &c.).
The view, often repeated, that the saccharum of the ancients is the hydrate of silica, sometimes found in bamboos and known in Arabian medicine as tabashir, is refuted by Yule, Anglo-Indian Glossary, p. 654; see also Not.
The alkali must be free from carbonate and an excess of it must be avoided, otherwise the hydrate redissolves.
Titanic oxide separates out as a white hydrate, which, however, is generally contaminated with ferric hydrate and often with tin oxide.
The solution, if boiled, deposits its titanic oxide as a hydrate called metatitanic acid, TiO(OH) 21 because it differs in its properties from orthotitanic acid, Ti(OH) 4, obtained by decomposing a solution of the chloride in cold water with alkalis.
The solution when boiled deposits most of its oxide in the meta-hydrate form.
Carbon monoxide takes part in the syntheses of sodium formate from sodium hydrate, or soda lime (at 200 0 -2 20 0), and of sodium acetate and propionate from sodium methylate and sodium ethylate at 160 0 -200°.
Semioxamazide, H 2 N CO CO-NH NH 2, is prepared by the action of hydrazine hydrate on oxamaethane (W.
The hydrate, Bi(OH) 3 i is obtained as a white powder by adding potash to a solution of a bismuth salt.
The hydrate, B1204.2H20, is also known.
Cailletet and later by P. Villard that when allowed to stand in the presence of water at a low temperature a solid hydrate is formed.
Chem., 1905 (2), 71, p. 45 2) by reducing osmium compounds with hydrazine hydrate in the presence of gum arabic.
The monoxide and its hydrate are more familiarly known as lime (q.v.) and slakedlime.
The dioxide was obtained as the hydrate, CaO 2.8H,0, by P. Thenard (Ann.
Anhydrous calcium chloride, prepared by heating the hydrate to 200° (preferably in a current of hydrochloric acid gas, which prevents the formation of any oxychloride), is very hygroscopic, and is used as a desiccating agent.
Pure potassium is a silvery white metal tinged with blue; but on exposure to air it at once forms a film of oxide, and on prolonged exposure deliquesces into a solution of hydrate and carbonate.
The remaining mud of calcium carbonate and hydrate is washed, by decantation, with small instalments of hot water to recover at least part of the alkali diffused throughout it, but this process must not be continued too long or else some of the lime passes into solution.
The liquors after a concentration in iron vessels are now evaporated in a silver dish, until the heavy vapour of the hydrate is seen to go off.
For the fusion of the dry hydrate nickel vessels cannot be used; in fact, even silver is perceptibly attacked as soon as all the excess of water is away; absolutely pure KHO can be produced only in gold vessels.
Werner, four hydrated chromium chlorides exist, namely the green and violet salts, CrC1 3.6H 2 O, a hydrate, CrC1 3.10H 2 O and one CrC1 3.4H 2 0.
Taking the point 0 to denote the state of equilibrium between ice, hydrate; saturated solution and vapour, we pass along OA till a new solid phase, that of Na2S04, appears at 32.6°; from this point arise four curves, analogous to those diverging from the point O.
The curve OP represents the varying solubility of the hydrate as the temperature rises from the cryohydric point to 32.6°.
At that temperature crystals of the anhydrous Na 2 SO 4 appear, and a new fixed equilibrium exists between the four phases - hydrate, anhydrous salt, solution and vapour.
This indicates the appearance of a new compound, which should exist pure at E, the next maximum, and, led by these considerations, Roozeboom discovered and isolated a previously unknown hydrate, Fe 2 C1 6 7 H 2 0.
In a similar way the curve FGH, between 30° and 55°, shows the effect of the hydrate Fe2Cl6.5H20, and the curve HJK that of the hydrate Fe 2 C1 6.4H 2 O, which, when pure, melts at 73.5° - the point J on the diagram.
A familiar example is to be found in solutions of sodium sulphate, which may be cooled much below their saturation point and kept in the liquid state till a crystal of the hydrate Na 2 SO 4 IoH 2 O is dropped in, when solidification occurs with a large evolution of latent heat.
Limonite is a ferric hydrate, conforming typically with the formula Fe 4 0 3 (OH) 6, or 2Fe 2 O 3.3H 2 O.
It is a physiological antagonist of chloral hydrate, morphine and physostigmine, and may be given in poisoning by these drugs.
To ensure this being properly done, the lumps of lime should be broken up small, and enough water to slake them should be added, the lime then being allowed to rest for about forty-eight hours, when the water changes the particles of quicklime to hydrate of lime, and breaks up the hard lumps into a powder.
Aluminium hydrate, Al(OH) 3, is obtained as a gelatinous white precipitate, soluble in potassium or sodium hydrate, but insoluble in ammonium chloride, by adding ammonia to a cold solution of an aluminium salt; from boiling solutions the precipitate is opaque.
By drying at ordinary temperatures, the hydrate Al(OH) 3 ï¿½H 2 0 is obtained; at 300° this yields A10(OH), which on ignition gives alumina, Al 2 O 3.
Precipitated aluminium hydrate finds considerable application in dyeing.
Both these soluble hydrates are readily coagulated by traces of a salt, acid or alkali; Crum's hydrate does not combine with dye-stuffs, neither is it soluble in excess of acid, while Graham's compound readily forms lakes, and readily dissolves when coagulated in acids.
In addition to behaving as a basic oxide, aluminium oxide (or hydrate) behaves as an acid oxide towards the strong bases with the formation of aluminates.