Word Finder - alkalis

definition

One of a class of caustic bases, such as soda, soda ash, caustic soda, potash, ammonia, and lithia, whose distinguishing peculiarities are solubility in alcohol and water, uniting with oils and fats to form soap, neutralizing and forming salts with acids, turning to brown several vegetable yellows, and changing reddened litmus to blue.

definition

(Western United States) Soluble mineral matter, other than common salt, contained in soils of natural waters.

On boiling their solution in caustic alkalis, ammonia is liberated.

Iron, which stands so well against aqueous alkalis, is most violently attacked by the fused reagents.

The alkalis are used almost exclusively in the condition of caustic lyessolutions of their respective hydrates in water.

Alcoholic solutions of the alkalis also produce much nitrite along with some formate and acetate.

This latter compound may be chlorinated to perchloracetoacrylic chloride (9), from which the corresponding acid (to) is obtained by treatment with water; alkalis hydrolyse the acid to chloroform and dichlormaleic acid (I I).

They are precipitated from their alkaline solutions as cobalt sulphide by sulphuretted hydrogen, but this precipitation is prevented by the presence of citric and tartaric acids; similarly the presence of ammonium salts hinders their precipitation by caustic alkalis.

It sublimes in thin plates of a dark colour and metallic lustre, and is soluble in solutions of the caustic alkalis.

Owing to their possession of this common property, these natural fatty bodies and various artificial derivatives of glycerin, which behave in the same way when treated with alkalis, are known as glycerides.

The simplest modes of preparing pure glycerin are based on the saponification of fats, either by alkalis or by superheated steam, and on the circumstance that, although glycerin cannot be distilled by itself under the ordinary pressure without decomposition, it can be readily volatilized in a current of superheated steam.

Iron and quinine citrate is used as a bitter stomachic and tonic. In the blood citrates are oxidized into carbonates; they therefore act as remote alkalis, increasing the alkalinity of the blood and thereby the general rate of chemical change within the body.

The process of manufacturing soaps by boiling fatty acids with caustic alkalis or sodium carbonate came into practice with the development of the manufacture of candles by saponifying fats, for it provided a means whereby the oleic acid, which is valueless for candle making, could be worked up. The combination is effected in open vats heated by a steam coil and provided with a stirring appliance; if soda ash be used it is necessary to guard against boiling over.

With genuine soaps, however, it suffices to calculate the fatty acids as anhydrides and add to this the amount of alkalis, and estimate the water by difference.

The complete analysis involves an examination of the fatty matter, of the various forms in which the alkalis are present - free and combined glycerin, &c.

The heptachlor compound when treated with chlorine water gives trichloraceto-pentachlorbutyric acid (6), which is hydrolysed by alkalis to chloroform and pentachlorglutaric acid (7), and is converted by boiling water into tetrachlor-diketo-Rpentene (8).

On fusion with caustic alkalis they decompose into their constituent aminothiophenol and acid.

Alkalis partially convert it into d-mannose and d-fructose.

Alkalis have little effect on it under ordinary circumstances, although prolonged contact with ammonia results in a partial change.

They are silicates, usually orthosilicates, of aluminium together with alkalis (potassium, sodium, lithium, rarely rubidium and caesium), basic hydrogen, and, in some species magnesium, ferrous and ferric iron, rarely chromium, manganese and barium.

Clarke (1889-1893) supposes them to be substitution derivatives of normal aluminium orthosilicate A14(S104)3, in which part of the aluminium is replaced by alkalis, magnesium, iron and the univalent groups (MgF), (A1F2),(AlO), (MgOH); an excess of silica is explained by the isomorphous replacement of H 4 SiO 4 by the acid H4S130s.

Its specific gravity is about 9; it is sparingly soluble in water, but readily dissolves in acids and molten alkalis.

They are characterized by the deep red colour of their solutions in alkalis.

By the action of alkalis it is converted into iso-eugenol, which on oxidation yields vanillin, the odorous principle of vanilla.

It gives mono-metallic salts of the type NC NHM when treated with aqueous or alcoholic solutions of alkalis.

They show all the reactions of esters, being readily hydrolysed by caustic alkalis, and reacting with ammonia to produce carhamic esters and urea.

But of the rest the majority, when treated with boiling sufficiently strong alkali, are attacked at least superficially; of ordinary metals only gold, platinum, and silver are perfectly proof against the reagents under consideration, and these accordingly are used preferably for the construction of vessels intended for analytical operations involving the use of aqueous caustic alkalis.

There is hardly a single metal which holds out against the alkalis themselves when in the state of fiery fusion; even platinum is most violently attacked.

In chemical laboratories fusions with caustic alkalis are always effected in vessels made of gold or silver, these metals holding out fairly well even in the presence of air.

It forms crystalline needles soluble in alkalis, chloroform and Zoo parts of water.

Of the ketoses, we notice d-sorbose, found in the berries of mountain-ash, and d-tagatose, obtained by Lobry de Bruyn and van Ekenstein on treating galactose with dilute alkalis, talose and l-sorbose being formed at the same time.

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.

A hydrated form is prepared when a solution of titanic acid in hydrochloric acid is digested with copper, or when the trichloride is precipitated with alkalis.

In common with Gay Lussac and Davy, he held subterraneous thermic disturbances to be probably due to the contact of water with metals of the alkalis and alkaline earths.

The causticity of alkaline bodies was explained at that time as depending on the presence in them of the principle of fire, "phlogiston"; quicklime, for instance, was chalk which had taken up phlogiston, and when mild alkalis such as sodium or potassium carbonate were causticized by its aid, the phlogiston was supposed to pass from it to them.

It is readily hydrolysed by hot solutions of the caustic alkalis.

It is only slightly soluble in water, but is readily soluble in acids and alkalis.

It dissolves in alkalis to form well-defined crystalline salts; potassium aurate, KAu0 2.3H 2 O, is very soluble in water, and is used in electrogilding.

The method of making these "mild" alkalis into "caustic" alkalis by treatment with lime was practised in the time of Pliny in connexion with the manufacture of soap, and it was also known that the ashes of shore-plants yielded a hard soap and those of land-plants a soft one.

Percy, the mineral matter being also changed by the removal of silica and alkalis and the substitution of substances analogous in composition to fire-clay.

In the case of liquids containing strong acids or alkalis, which the paper cannot withstand, a plug of carefully purified asbestos or glass-wool (spun glass) is often employed, contained in a bulb blown as an enlargement on a narrow "filtertube."

The monometallic salts of the alkalis and alkaline earths may be obtained in crystal form, but those of the heavy metals are only stable when in solution.

If the heating be with charcoal, the trimetallic salts of the alkalis and alkaline earths are unaltered, whilst the monoand di-salts give free phosphorus and a trimetallic salt.

Tt is a monacid base which is readily soluble in solutions of the cans' is alkalis.

It is incompatible with carbonates of the alkalis.

The gas is rapidly absorbed by solutions of the caustic alkalis, with the production of alkaline carbonates (q.v.), and it combines readily with potassium hydride to form potassium formate.

It Is Easily Soluble In Solutions Of The Caustic Alkalis, Provided They Are Not Too Concentrated, Forming Solutions Of Alkaline Carbonates And Sulphides, Cos 4Kho = K2C03 K 2 S 2H20.

Like all alkalis if given in quantities they increase metabolism.

The resins which are obtained as natural exudations are in general mixtures of different, peculiar acids, named the resin acids, which dissolve in alkalis to form resin soaps, from which the resin acids are regenerated by treatment with acids.

In the ordinary laboratory the Bunsen flame has become universal, and a number of substances, such as the salts of the alkalis and alkaline earths, show characteristic spectra when suitably placed in it.

It is, however, more readily ob tained by boiling citraor meso-brompyrotartaric acids with alkalis.

The antidotes are mild alkalis, together with the use of opium to relieve pain.