Cobalt monoxide, CoO, is prepared by heating the hydroxide or carbonate in a current of air, or by heating the oxide C0304 in a current of carbon dioxide.
Sodium hydroxide) will in a solid state fire it on contact.
Iridium tetrachloride, IrC1 41 is obtained by dissolving the finely divided metal in aqua regia; by dissolving the hydroxide in hydrochloric acid; and by digesting the hydrated sesquichloride with nitric acid.
The cobaltous salts are formed when the metal, cobaltous oxide, hydroxide or carbonate, are dissolved in acids, or, in the case of the insoluble salts, by precipitation.
By electrolysis it yields uranium dioxide as a pyrophoric powder, and peruranic hydroxide, U04.2H20, when treated with hydrogen peroxide.
Dry guncotton heated in ammonia gas detonates at about 70°, and ammonium hydroxide solutions of all strengths slowly decompose it, yielding somewhat complex products.
Another heat test, that of Will, consists in heating a weighed quantity of the guncotton in a stream of carbon dioxide to 130° C., passing the evolved gases over some red-hot copper, and finally collecting them over a solution of potassium hydroxide which retains the carbon dioxide and allows the nitrogen, arising from the guncotton decomposition, to be measured.
The action is very rapid, and the product, which rises to the top of the acids, is separated and washed successively with cold and then tepid water, and finally with water made slightly alkaline with sodium carbonate or hydroxide, to remove all adhering or dissolved acids which would otherwise render the product very unstable.
Sodyl hydroxide, NaHO 2, exists in two forms: one, Na O.OH, obtained from hydrogen peroxide and sodium ethylate; the other, 0 :Na OH, from absolute alcohol and sodium peroxide at 0 °.
The cadmium sulphate solution is prepared by digesting a saturated solution of cadmium sulphate with cadmium hydroxide to remove free acid, care being taken not to raise the temperature above 70° C., and then by digesting it still further with mercurous sulphate until no more precipitation occurs.
The monoxide, K 2 0, may be obtained by strongly heating the product or burning the metal in slightly moist air; by heating the hydroxide with the metal: 2KHO+2K= 2K 2 0+H 2; or by passing pure and almost dry air over the molten metal (Kiihnemann, Chem.
This hydroxide is soluble in well cooled acids, forming solutions which contain cobaltic salts, one of the most stable of which is the acetate.
It dissolves easily in water, forming the hydrated chloride, CoC12.6H20, which may also be prepared by dissolving the hydroxide or carbonate in hydrochloric acid.
Sainte-Claire Deville obtained a grey product, from which, on dissolving out the aluminium with sodium hydroxide, they obtained a crystalline product, which they thought to be a modification of boron, but which was shown later to be a mixture of aluminium borides with more or less carbon.
Cadmium hydroxide, Cd(OH) 2, is obtained as a white precipitate by adding potassium hydroxide to a solution of any soluble cadmium salt.
It is decomposed by heat into the oxide and water, and is soluble in ammonia but not in excess of dilute potassium hydroxide; this latter property serves to distinguish it from zinc hydroxide.
Nagel (Ber., 1898, 31, p. 2009), this oxide does not exist, the reaction leading to the formation of an hydroxide according to the equation: Mo 3 C1 4 (OH) 2 + 4KHO 3H 2 O = 3Mo(OH) 3 -l-4KBr+3H.
Molybdenum sesquioxide, Mo 2 O 3, a black mass insoluble in acids, is formed by heating the corresponding hydroxide in vacuo, or by digesting the trioxide with zinc and hydrochloric acid.
It is a yellow amorphous powder which is soluble in dilute alkalis, the solution on acidification giving an hydroxide, C1 4 Mo 3 (OH) 2, which is soluble in nitric acid, and does not give a reaction with silver nitrate.
The solution obtained may be evaporated in vacuo until it attains a density of 1.46 when, if partially saturated with potassium hydroxide and filtered, it yields crystals of potassium pentathionate, K 2 S 5 0 6.3H 2 0.
The next group precipitate may contain the white gelatinous aluminium hydroxide, the greenish chromium hydroxide, reddish ferric hydroxide, and possibly zinc and manganese hydroxides.
Treatment with casutic soda dissolves out aluminium hydroxide, which is reprecipitated by the addition of ammonium chloride.
It is also prepared by heating ammonium nitrite (or a mixture of sodium nitrite and ammonium chloride): NH 4 NO 2 =2H20+N21 by heating a mixture of ammonium nitrate and chloride (the chlorine which is simultaneously produced being absorbed by milk of lime or by a solution of sodium hydroxide): 4NH4N03+2NH4C1=5N2 +C1 2 +12H 2 O; by heating ammonium dichromate (or a mixture of ammonium chloride and potassium dichromate): (NH4)2Cr207 = Cr203+4H20+ N2; by passing chlorine into a concentrated solution of ammonia (which should be present in considerable excess): 8NH3+3C12=6NH4C1-F-N2; by the action of hypochlorites or hypobromites on ammonia: 3NaOBr-+2NH 3 =3NaBr+3H 2 OH-N 2; and by the action of manganese dioxide on ammonium nitrate at 180-20o° C. It is also formed by the reduction of nitric and nitrous oxides with hydrogen in the presence of platinized asbestos at a red heat (G.
Sodium nitrite, the most commonly used salt of the acid, is generally obtained by heating the nitrate with metallic lead; by heating sodium nitrate with sulphur and sodium hydroxide, the product then being fractionally crystallized;(Read, Holliday & Sons): 3NaNO 3 +S+2NaOH = Na2S04+3NaN02+H20; by oxidizing atmospheric nitrogen in an electric arc, keeping the gases above 300° C., until absorption in alkaline hydroxide solution is effected (German Pat.
Ammonium hydroxide has no appreciable action at ordinary temperatures, but strong solutions of sodium or potassium hydroxides start a decomposition, with rise of temperature, in which some nitrate and always some nitrite is produced.
With potassium hydroxide it yields potassium silicofluoride,.
Whilst with sodium hydroxide, sodium fluoride is produced: 3SiF4= 4KHO = S102+ 2K 2 SiF 6 + 2H 2 0; SiF 4 + 4NaOH = SiO 2 + 4NaF+ 2H 2 O.
It is decomposed readily by water, sodium hydroxide, alcohol and ether: 2SiHF 3 +4H 2 0 = H 4 S10 4 +H 2 SiF 6 -1-211 2; SiHF 3 +3NaOH H 2 O =H4S104+3NaF+H2; 2SiHF 3 +4C 2 H 5 OH =Si(0C 2 H 5) 4 +H 2 SiF 6 +2H 2 i SiHF 3 +3(C 2 H 5) 2 0 =SiH(OC2H5)3+3C2H5F.
The acid carbonates of the alkali metals can be prepared by saturating an aqueous solution of the alkaline hydroxide with carbon dioxide, M OH+ C02= Mhco 3, and from these acid salts the normal salts may be obtained by gentle heating, carbon dioxide and water being produced at the same time, 2Mhco 3 = M2C03+H02+C02.
This substance absorbs and combines with water very greedily, at the same time becoming very hot, and falling into a fine dry powder,' calcium hydroxide or slaked lime, which when left in the open slowly combines with the carbon dioxide of the air and becomes calcium carbonate, from which we began.
Boiling water attacks it appreciably, but slightly, with evolution of hydrogen and formation of the hydroxide, Zn(OH) 2.
Zinc and hydrochloric acid in the cold convert it into alloxantin, hydroxylamine gives nitroso-barbituric acid, C 4 H 2 N 2 0 3: NOH, baryta water gives alloxanic acid, C 4 H 4 N 2 0 5, hot dilute nitric acid oxidizes it to parabanic acid, hot potassium hydroxide solution hydrolyses it to urea and mesoxalic acid and zinc and hot hydrochloric acid convert it into dialuric acid, C4H4N204.
Potassium hydroxide or caustic potash, KOH, formerly considered to be an oxide but shown subsequently to be a hydroxide of potassium, may be obtained by dissolving the metal or monoxide in water, but is manufactured by double decomposition from potassium carbonate and slaked lime: K 2 CO 3 -E-Ca(OH) 2 =2KOH+CaC03.
- Potassium fluoride, KF, is a very deliquescent salt, crystallizing in cubes and having a sharp saline taste, which is formed by neutralizing potassium carbonate or hydroxide with hydrofluoric acid and concentrating in platinum vessels.
Sodium hydroxide has certain advantages compared with chloride, although it is more costly; its fusing-point is only 320° C., and no anode chlorine is produced, so that both containing vessel and anode may be of iron, and no porous partition is necessary.
Exposed to moist air it rapidly oxidizes to the hydroxide; and it burns on heating in air with a yellow flame, yielding the monoxide and dioxide.
Soc., 1893, 65, p. 890) obtained NaOH H 2 O from hot concentrated solutions and NaOH 2H 2 O from a solution of the hydroxide in 96.8% alcohol.
The aqueous solution of ammonia is very basic in its reactions, and since it is a weak electrolyte, one must assume the solution to contain a certain amount of ammonium hydroxide NH 4 OH, although it is probably chiefly composed of a solution of ammonia in water.
The amount of ammonia in ammonium salts can be estimated quantitatively by distillation of the salts with sodium or potassium hydroxide, the ammonia evolved being absorbed in a known volume of standard sulphuric acid and the excess of acid then determined volumetrically; or the ammonia may be absorbed in hydrochloric acid and the ammonium chloride so formed precipitated as ammonium chlorplatinate, (NH4)2PtC16.
A basic nitrate, Ca(NO 3)2 Ca(OH) 2.3H 2 0, is obtained by dissolving calcium hydroxide in a solution of the normal nitrate.
Zirconium hydroxide, Zr(OH) 4, as thus obtained, is quite appreciably soluble in water and easily in mineral acids, with formation of zirconium salts, e.g.
But, if the hydroxide is precipitated in the heat, it demands concentrated acids for its solution.