noun
definition
An univalent anion (OH-) based on the hydroxyl functional group.
definition
Any substance containing such an anion.
Examples of hydroxide in a Sentence
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.
It polymerizes to a tetrose under the action of sodium hydroxide.
The nitrate, Al(N03)3, is obtained as deliquescent crystals (with 81120) by evaporating a solution of the hydroxide in nitric acid.
These results point to the conclusion that the iso-diazo hydroxide is a tautomeric substance.
Similar results have been obtained by using diazotized para-anisidine, a synand an anticompound being formed, as well as a third isomeric cyanide, obtained by evaporating para-methoxybenzenediazonium hydroxide in the presence of an excess of hydrocyanic acid at ordinary temperatures.
Benzene diazonium hydroxide, although a strong base, reacts with the alkaline hydroxides to form salts with the evolution of heat, and generally behaves as a weak acid.
On mixing dilute solutions of the diazonium hydroxide and the alkali together, it is found that the molecular conductivity of the mixture is much less than the sum of the two electrical conductivities of the solutions separately, from which it follows that a portion of the ions present have changed to the non-ionized condition.
Lanthanum hydroxide, La(OH) 3, is a white amorphous powder formed by precipitating lanthanum salts by potassium hydroxide.
The iron and aluminium precipitates are filtered off, and the filtrate boiled, when a basic beryllium hydroxide containing a little ferric oxide is precipitated.
The hydroxide Be(OH)2 separates as a white bulky precipitate on adding a solution of an alkaline hydroxide to a soluble beryllium salt; and like those of aluminium and zinc, this hydroxide is soluble in excess of the alkaline hydroxide, but is reprecipitated on prolonged boiling.
Beryllium salts are easily soluble and mostly have a sweetish taste (hence the name Glucinum, from yXv,dc, sweet); they are readily precipitated by alkaline sulphides with formation of the white hydroxide, and may be distinguished from salts of all other metals by the solubility of the oxide in ammonium carbonate.
Rock-salt when pure is colourless and transparent, but is usually red or brown by mechanical admixture with ferric oxide or hydroxide.
It will be observed that in the hydration of tricalcium silicate, the main constituent of Portland cement, a large portion of the lime appears as calcium hydroxide, i.e.
A blue basic salt is precipitated first, which, on boiling, rapidly changes to the rose-coloured hydroxide.
It is also obtained by heating para-chlorphenoldisulphonic acid with potassium hydroxide.
Gay-Lussac in 181q, is usually obtained in the form of its barium salt by suspending freshly precipitated hydrated manganese dioxide in water and passing sulphur dioxide into the mixture until all is dissolved; the barium salt is then precipitated by the careful addition of barium hydroxide.
A hydrated dioxide, approximating in composition to SrO 2.8H 2 O, is formed as a crystalline precipitate when hydrogen peroxide is added to an aqueous solution of strontium hydroxide.
Traces of ethyl alcohol in solutions are detected and estimated by oxidation to acetaldehyde, or by conversion into iodoform by warming with iodine and potassium hydroxide.
Metallic sodium possesses a silvery lustre, but on exposure to moist air the surface is rapidly dulled by a layer of the hydroxide.
It forms a grey mass, which melts at a red heat and violently combines with water to give the hydroxide.
The iodides can be prepared either by direct union of iodine with a metal, from hydriodic acid and a metal, oxide, hydroxide or carbonate, or by action of iodine on some metallic hydroxides or carbonates (such as those of potassium, sodium, barium, &c.; other products, however, are formed at the same time).
Sodium and potassium hydroxide solutions precipitate green chromium hydroxide from solutions of chromic salts; the precipitate is soluble in excess of the cold alkali, but is completely thrown down on boiling the solution.
Chromous oxide, CrO, is unknown in the free state, but in the hydrated condition as Cr04H 2 0 or Cr(OH) 2 it may be prepared by precipitating chromous chloride by a solution of potassium hydroxide in air-free water.
The sesquioxide, Cr 2 0 3, occurs native, and can be artificially obtained in several different ways, e.g., by igniting the corresponding hydroxide, or chromium trioxide, or ammonium bichromate, or by passing the vapours of chromium oxychloride through a red-hot tube, or by ignition of mercurous chromate.
Chromic sulphate, Cr2(S04)3, is prepared by mixing the hydroxide with concentrated sulphuric acid and allowing the mixture to stand, a green solution is first formed which gradually changes to blue, and deposits violet-blue crystals, which are purified by dissolving in water and then precipitating with alcohol.
The nitrate, Cr(NO 3) 3.9H 2 0, crystallizes in purple prisms and results on dissolving the hydroxide in nitric acid, its solution turns green on boiling.
Chromic thiocyanate, Cr(SCN) 3, an amorphous deliquescent mass, is formed by dissolving the hydroxide in thiocyanic acid and drying over sulphuric acid.
Magnesium Oxide, magnesia, MgO, occurs native as the mineral periclase, and is formed when magnesium burns in air; it may also be prepared by the gentle ignition of the hydroxide or carbonate.
Magnesium hydroxide Mg(OH) 2, occurs native as the minerals brucite and nemalite, and is prepared by precipitating solutions of magnesium salts by means of caustic soda or potash.
Magnesium hydroxide is a white amorphous solid which is only slightly soluble in water; the solubility is, however, greatly increased by ammonium salts.
It may be prepared by dissolving the metal, its oxide, hydroxide, or carbonate in dilute hydrochloric acid, or by mixing concentrated solutions of magnesium sulphate and common salt, and cooling the mixture rapidly, when the less soluble sodium sulphate separates first.
Water decomposes it with liberation of ammonia and formation of magnesium hydroxide.
Its action upon turmeric is characteristic; a turmeric paper moistened with a solution of boric acid turns brown, the colour becoming much darker as the paper dries; while the addition of sodium or potassium hydroxide turns it almost black.
Seeing that sodium was the only possible reducing agent, he set himself to cheapen its cost, and deliberately rejecting sodium carbonate for the more expensive sodium hydroxide (caustic soda), and replacing carbon by a mixture of iron and carbon - the so-called carbide of iron - he invented the highly scientific method of winning the alkali metal which has remained in existence almost to the present day.
The solution of sodium aluminate, containing aluminium oxide and sodium oxide in the molecular proportion of 6 to 1, is next agitated for thirty-six hours with a small quantity of hydrated alumina previously obtained, which causes the liquor to decompose, and some 70% of the aluminium hydroxide to be thrown down.
Alumina is obtained as a white amorphous powder by heating aluminium hydroxide.
But the hydroxide of thallium, in most of its properties, comes very close to the alkali metals; it is strongly basic, forms an insoluble chloroplatinate, and an alum strikingly similar to the corresponding potassium compounds.
When kept in contact with water and air it is gradually converted into hydroxide, T10H.
Thallous hydroxide, T10H, is most conveniently prepared by decomposing the solution of the sulphate with baryta water.
Thallic hydroxide, TI(OH) 31 is obtained as a brown precipitate by adding a hot solution of thallous chloride in sodium carbonate to a solution of sodium hypochlorite.
The hydroxide is obtained as brown hexagonal plates by fusing thallic oxide with potash to which a little water has been added.
Manganous hydroxide, Mn (OH) 2, is obtained as a white precipitate on adding a solution of a caustic alkali to a manganous salt.
By the addition of caustic soda to cerous salts, a white precipitate of cerous hydroxide is formed.
By suspending the precipitated cerous hydroxide in water and passing chlorine through the solution, a hydrated form of the dioxide, 2CeO 2.3H 2 O, is obtained, which is readily soluble in nitric and sulphuric acids, forming ceric salts, and in hydrochloric acid, where it forms cerous chloride, with liberation of chlorine.
Cerium compounds may be recognized by the red precipitate of ceric hydroxide, which is formed when sodium hypochlorite is added to a colourless cerous salt.
The object of the latter is to convert the manganous hydroxide by the atmospheric oxygen into manganese dioxide, but this would take place much too slowly if there was not an excess of lime present ready to combine with the manganese dioxide to form a calcium manganite.
Potassium thorofluoride, K2ThF6 4H20, is a heavy black powder formed by boiling the hydroxide with potassium fluoride and hydrofluoric acid.
A number of salts of thorium have been prepared for therapeutic use, including the hydroxide, nitrate, salicylate, oleate and lactate.
The monoxide, NiO, occurs naturally as bunsenite, and is obtained artificially when nickel hydroxide, carbonate, nitrate or sulphate is heated.
The hydroxide, Ni(OH) 2, is obtained in the form of a greenish amorphous powder when nickel salts are precipitated by the caustic alkalis.