The ferro- and ferricyanide ions may also be treated as complex ions.
If the fact is recalled that the extremely sensitive tests for the ferric-ion fail to reveal the least trace of it in a potassium ferricyanide solution, one must conclude that the ferricyanide-ion must be extremely stable.
Thiocyanates do not produce even the faintest tinge of pink in potassium ferricyanide solution[163]; ammonium hydroxide does not precipitate any ferric hydroxide (‹exps.
The yellow color of the ion moving to the positive electrode shows the presence of the iron in it—a fact that can be confirmed by testing the solution round the anode for ferricyanide by the method discussed further on in the text.
It gives precipitates with alkaloidal group reagents, and strikes a blue colour with ferric chloride and ferricyanide of potassium.
Oxidation of an aniline salt by means of a solution of ferricyanide of potassium.
Ferricyanide of potassium deepens the colour, but does not give a blue precipitate, as it does with ferrous salts (proto salts).
The commercial Prussian blue is not pure ferrocyanide of iron, but a mixture of this salt with varying proportions of the ferricyanide of iron and potassium, which also has a fine deep blue colour.
Precipitate a solution of protosulphate of iron with another of red prussiate of potash (ferricyanide of potassium.
Ferricyanide of potassium produces a rich deep-blue precipitate, insoluble in hydrochloric acid.
I have used with success the ferricyanide of potassium (the red prussiate of potash, as it is called) for removing the stains contracted in photographing.
They combine readily with the alkyl iodides to form alkyl acridinium iodides, which are readily transformed by the action of alkaline potassium ferricyanide to N-alkyl acridones.
Potassium ferricyanide costs about twenty cents per pound, and a pound is ample for a lifetime.
Without encouraging the reader to be careless let it be said that "any old formula" (of ferricyanide and bromide) for the bleacher will prove successful.
Dissolve the ounce of potassium ferricyanide in 10 ounces of water.
If the print has been dried, it is only necessary to soak it for a few moments in a fresh fixing bath, when the ferricyanide can be applied as before.
The ferricyanide suffers in time by exposure to daylight; but, as both it and the bromide are comparatively cheap and serve for a large number of prints, there is no need to take excessive care.
In a separate graduate put 1 dram offerricyanide solution and 5 ounces of water.
A very dense negative, for instance, may be reduced either with the ferricyanide of potash or persulphate of ammonia reducer; and a thin negative with proper graduations can frequently be intensified to advantage in the print.
In the case of many formulae, it will be noticed that equal quantities of bromide and ferricyanide are recommended.
Although, as just stated, variations in the formula are not at all marked in their effects, a proportion of bromide over one-quarter of the ferricyanide does tend towards the yellowish color of which complaints are now and again heard.
If not washed long enough, the yellow of the ferricyanide will remain in the print, robbing its gradations of brightness and purity of color and impairing the permanency of the print.
But the best of the lot is a solution of the two substances potassiumferricyanide and potassium bromide, which forms an image of silver ferrocyanide and silver bromide.
If, however, only a portion of the print needs reduction, this can be effected by applying the ferricyanide solution locally with a brush or bit of absorbent cotton.
The ferricyanide-bromide mixture, however, keeps very much better than a plain solution of ferricyanide alone.
Ferricyanide solutions give with ferrous salts a deep blue precipitate; with ferric salts a dark-brown coloration.
That test was applied to these extracts when no morphia was present,—the reduction of the ferricyanide to the ferro-cyanide of potassium.
The only common ones are ferro-and ferricyanide of potassium, the so-called yellow and red prussiates of potash.
Expose until the image is visible, then develop by floating on a solution of potassium ferricyanide at 5 per 100 of water—the image appears at once with a rich brown color.
If in place of gallic acid I use a diluted solution of potassium ferricyanide (red prussiate of potash), Prussian blue is formed in the parts acted on by light.
This was confirmed by a well-marked reaction with ferric ferricyanide with increase of weight due to the fixation of the blue cyanide.
The ferric ferricyanide reaction is inhibited by the disappearance of the reactive groups, upon which this curious and characteristic phenomenon depends (1st ed.
To determine the finishing point, place a series of drops of the ferricyanide solution on a dry white glazed plate.
The ferricyanide had a small influence and, as might be expected, hyposulphite is fatal to the assay.
Ferricyanide of potassium gives a blue precipitate or green coloration; with ferric salts a brown colour only is produced.
Some of these, ferrocyanide and ferricyanide of potassium for example, have such characteristic properties that the fact that they are cyanides may be overlooked.
In case of need, the ferricyanide can be purified by adding to its solution a little bromine water and recrystallizing the compound.
Prepare a fresh solution, as needed each day, by dissolving a crystal of potassiumferricyanide about the size of a pin's head in 25 cc.
The reaction is rendered more sensitive if alcohol is carefully poured on the solution after it has been rendered alkaline, and potassium ferricyanide is then added.
In most cases a blue coloration will appear; the addition of 1-2 drops of potassium ferricyanide solution with formation of a blue coloration indicates the presence of Neradol ND without fail.
I have here in solution uranium nitrate, plus potassium ferricyanide acidified with acetic acid.
The ferricyanide reducer can be applied locally for reducing high-lights, halated windows, etc.
The mixture of hypo and ferricyanide is carefully applied with a camel's hair brush to the parts that are too opaque, and after a few moments the plate is allowed to slip back into the hypo solution and the dish is rocked.
A great deal can be done to improve a hard negative as soon as it leaves the fixing bath, by applying a mixture of hypo solution and a solution of ferricyanide (not ferro) of potash with a piece of cotton wool to the dense parts.
The simplest solution to use for this purpose is known as the Howard Farmer reducer and is a solution of hypo mixed with a small quantity of potassium ferricyanide (red prussiate of potash).
The rapidity of the reducing action depends on the proportion of ferricyanide solution added, and it is very important not to add too much, otherwise the process gets out of control and reduction goes too far.
The cloud may cover the whole of the second slide, and that part of it not required may be wiped out by means of a reducing solution, used with a brush, such as the ferricyanide and hypo one described later.
The green fog will gradually disappear and some more of the ferricyanide may be added, if necessary, to secure this end, but it is important to keep the proportion of ferricyanide as low as possible, otherwise the image itself will be reduced.
A small quantity of hypo and ferricyanide solution is mixed in a measuring glass or some other suitable vessel.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "ferricyanide" in a variety of sentences. We hope that you will now be able to make sentences using this word.
