The alkalis do, however, acquire some degree of causticity in a strong fire, as appears from their being more easily united with spirit of wine after having been kept in fusion for some time.
The translator has made many experiments on the effect of the alkalisand neutral salts when mixed with colours, and has every reason to be satisfied with the addition of soda, when properly used.
In the preparation of Prussian-blue, alkalis are employed.
This vermilion is still only a cinnabar, which, however, approximates the pure red, and it may be conjectured that alkalis are used to bring it nearer to the culminating point.
Alkalis and their carbonates, lime water, carbonate of calcium, magnesia and its carbonate give green precipitates with ferrous and brown with ferric salts.
It forms red crystalline double salts with the chlorides of the metals of the alkalis and of the magnesium group.
Let us take another example: All alkalis float in water; All alkalis are metals: Therefore some metals float in water.
The treatment of fats in this way with caustic alkalis is called "saponification.
Alkalis are not the only substances which neutralize acids.
Since the caustic alkalis are extremely soluble in water, they do not crystallize as do most of the compounds previously described.
In order to bring the properties of alkalis into contrast with those of acids, we cannot do better than make a few simple experiments with a weak solution of washing soda.
There are two classes of alkalis distinguished by the terms caustic and mild.
For very special purposes, the caustic alkalis are sometimes made by the action of the metals on water, but for production on a large scale, less expensive methods are adopted.
The liberation of carbon dioxide on the addition of acids shows that the mild alkalis are carbonates.
The disintegrating action of the caustic alkalis is also illustrated by the use of caustic soda in the preparation of wood pulp for paper making.
All alkalis or carbonates of the alkalis have a directly opposite effect upon the printed layer to that last referred to.
The most intense forms of inflammation of the stomach are the toxic conditions which follow the swallowing of corrosive poisons, such as strong mineral acids of alkalis which may extensively destroy the mucous membrane.
A solution of caustic potash or soda forms with gentianin a yellow solution, and the tincture of the root to which either of these alkalis has been added loses its bitterness in a few days.
This Salt, as Mr. Geoffroy observed, differs from the common Volatile Alkalis in the form of its crystals; which made that Chymist justly consider it as a Salt of a somewhat Ammoniacal nature; a kind of Essential Salt of flesh.
Fixed Alkalis also coagulate Milk; but at the same time they separate the Whey from the Cheese, which floats on the liquor in clots.
The best way of freeing these Oils from their redundant Acid is to distil them frequently from Alkalis and Absorbents.
Fixed alkalis and mercury, both of which have more affinity with sulphur than with arsenic, may be very properly employed on this occasion.
It is very extraordinary that Tartar, which of itself is not soluble in water, should be soluble therein when become a neutral salt by uniting either with alkalisor with absorbent earths, or even with metals.
This may appear surprizing when we consider that, as Acids have a greater affinity with Alkalis than with metallic substances, the Acid of Sea-salt ought not to quit its basis, which is Alkaline, to unite with Mercury.
Fixed Alkalis and fatty matters are very fit to produce that separation.
Hence it might be concluded, that, of all substances, next to the Phlogiston and the Fixed Alkalis, Volatile Alkalis have the greatest affinity with acids in general.
Volatile Alkalis have a great affinity with acids, unite therewith rapidly and with ebullition, and form with them neutral salts, which shoot into crystals, but differ from one another according to the kind of acid employed in the combination.
In burns from alkalis or acids, wash off as quickly as possible and neutralize (make inactive the acids with baking soda, weak ammonia or soapsuds; the alkalis with vinegar or lemon juice).
The ancient glass has worn very thin, pitted almost through like a worn-out thimble with little holes where the alkalis have worked their way out.
It is precipitated as the metal from solutions of its salts by the metals of the alkalis and alkaline earths, zinc, iron, copper, &c.
The study of the action of alkalis on sugar has, however, yielded still further information as regards the mechanism of the reaction by which lactic acid is formed.
The direct formation of alcohol from sugar by the action of alkalis appears first to have been observed by Duclaux [1886], who exposed a solution of glucose and caustic potash to sunlight and obtained both alcohol and carbon dioxide.
This scheme agrees well with the current ideas as to the formation of lactic acid from glucose under the influence of alkalis (p.
The continued action even of dilute alkaline solutions carries the change much further and brings about a complex decomposition which is much more rapidly effected by more concentrated alkalis and at higher temperatures.
The following are the stages of this series: (1) Glucose, fructose, and mannose are converted byalkalis into lactic acid along with other products.
Löb has adduced many striking facts in favour of this view, and has shown that very dilute alkalis produce no lactic acid but formaldehyde and a pentose as primary products.
No doubt what gave special zest to his study of the alkalis was the hope of overthrowing the doctrine of French chemists that oxygen was the essential element of every acid.
In the following year Davy reported other chemical changes produced by electricity; he had succeeded in decomposing the fixed alkalis and discovering the elements potassium and sodium.
They also condense with aldehydes, under the influence of alkalis or sodium ethylate (L.
It is soluble in water, the solution showing an acid reaction, owing to the formation of aceto-acetic acid, and withalkalis it yields acetates.
Silica is easily attacked byalkalis and by lime, less readily by copper oxide, and still less by iron oxide.
It is, of course, very readily acted upon by solutions of alkalis and alkaline salts.
Since there is considerable choice in utensils made from different materials, the housekeeper may like to know something about these materials and about their care, and the effect of acids and alkalis upon them.
Great care must be used not to use cleaning powders which contain strong alkalis for cleaning aluminum ware.
Alkalis have a caustic taste, and turn red litmus solution blue.
But whereas caustic alkalis have not much effect on vegetable fibres, if kept out of contact with the air, the animal fibres are very quickly attacked.
These will also impress upon our minds the effects of acids and alkalis on the different kinds of fibres.
Alkalis have a very considerable action on fur and wool, but the effects vary a good deal according to the kind of alkali used, the strength and the temperature of the solution, as also, of course, the length of period of contact.
At first litmus and cochineal tinctures were used, but in testing crude alkalis containing alumina and iron, it was found that lakes were formed with these colours, and they become precipitated in the solution, and so no longer sensitive.
The specific gravities of acids and alkalis in solution are made use of in works, etc.
The alkalis are very interesting; often they form 5 or 10% of the whole rock; they indicate abundance of white micas or of undecomposed particles of felspar.
Either by rapid growth of vegetation, or by subsequent percolation of organic solutions, most of the alkalis and the lime have been carried away.
The felspar decomposes into kaolin and quartz; its alkalis are for the most part set free and removed in solution, but are partly retained in the white mica which is constantly found in crude china-clays.
We must absolutely condemn the use of any but mild vegetable acids in souring or scouring the leather, or in the dye bath, and as far as possible would avoid the use of acids and alkalis on tanned leather, both being equally injurious.
Metallic salts convert it to a violet black, salts of tin change it to pink, alkalis to blue, and acids to yellow.
It is not possible to understand the nature of their common properties without examining a class of substances called alkalisor bases.
All alkaliscontain oxygen and hydrogen in equal proportions.
It was found that the common properties of acids are a sour taste, ability to combine with alkalis in the formation of salts, and that all acids contain hydrogen.
This fatty acid then combines with the alkalis of the bile and of the pancreatic juice to form soap.
An instrument for measuring the alkaline force or purity of any of the alkalis of commerce.
The alkalisenable us to detect the presence of other oils, as that of turpentine or sassafras, in that of cloves, because they fix the latter, while the former may be volatilized with water by distilling the mixture.
The alkalis of manufacturing importance are, ammonia, potash, soda, and quinia.
By this time, the hematine has become decomposed, and cannot be restored to its pristine state by neutralizing the alkalis with acids.
It has been said that glass made from silica and alkalis alone, will not resist the action of water, but that the addition of a little lime is necessary for this effect.
Fresh precipitated thorina is a hydrate, which dissolves readily in the above acids, as well as in solutions of the carbonates of potash, soda, and ammonia, but not in these alkalis in a pure state.
A considerable portion of the mingledalkalis disappear in this operation, as if they entered into combination with the oil in the interior of the cotton filaments.
The same three alkalis have an acrid, and somewhat urinous taste; the first two are energetic solvents of animal matter; and the three combine with oils, so as to form soaps.
The carbonates of alkalisdo not produce these changes.
Alkalis do not dissolve it, but concentrated sulphuric acid forms with it a dark yellow dye, from which water causes no precipitation; wool extracts the colour from the acid solution, and becomes of a dirty brown hue.
The results of this research, and his subsequent work on the alkalis and on muriatic acid and chlorine, have been already described.
Up to this time metallic calces, and for the most part alkalis and earths also, had been regarded as elementary substances.
So far Davy's discoveries had all tended to confirm the generally accepted view which regarded alkalis and earths as metallic oxides.
Acids, alkalisand salts all contain, according to Stahl (beginning of the eighteenth century), more or less primordial acid.
And in the same note-book he suggests methods which he thinks might effect the decomposition of muriatic and boric acids, the alkalis and earths.
He showed that the properties of mild alkalis differ from those of caustic alkalis, because the composition of the former differs from that of the latter; and he showed exactly wherein this difference of composition consists, viz.
Earths and alkalis are probably oxides of metals; this before long became an article of faith with all orthodox chemists.
It has already been pointed out that Lavoisier considered the alkalis and the alkaline earths as elements, because in his time they had not been decomposed.
Thus the ions of the alkalis and magnesium are caustic, those of the alkaline earthy metals produce actual mortification of the tissue and so on.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "alkalis" in a variety of sentences. We hope that you will now be able to make sentences using this word.
