If no free acid is present, the liquid will not redden litmus-paper, or give an acid reaction with any of the numerous tinctorial agents in use by the chemist for the purposes of titration.
On most matters the stain is more or less reddish; after a little time no free acid may be detected, by simply moistening the spot; but if the stain is cut out and boiled with water, there may be some evidence of free acid.
For the arsenious acid solution arsenite of soda is substituted, and for the indigo solution a colourless iodised paper, which is turned blue by the smallest quantity of free acid.
After 6 or 8 hours the process is generally complete, and the liquid contains merely a trace of free acid, from which it may be separated.
This salt must be present in each titration in considerable excess, to prevent the interference of free acid.
The titration is more limited in its application than either of the oxidising processes because of the restrictions as to bulk, quality and quantity of free acid present, and other conditions of the solution to be assayed.
Free acid is necessary for these assays; if there is an insufficiency, the assay solution, instead of immediately decolorising the permanganate, assumes a brown colour.
The maximum reducing effect of zinc is obtained by exposing as large a surface as possible of the metal in a hot concentrated solution containing but little free acid (Thorpe).
It is well established that the controlling factor in the growth of bacteria in so far as "reaction" is concerned is not the titratable substances present but only the "free acid," i.
If these little particles be washed thoroughly in pure water, and then placed in a solution of sugar, lactic acidification immediately commences in the saccharine liquid, and goes on steadily until stopped by the excess of free acid.
It should be remembered that both these salts are hydrolyzed in solution, and therefore increase slightly the amount of free acid present.
An increase in the proportion of hypo is usual with an increase in the amount of free acid in an acid chroming bath.
The figure thus indicates approximately the degree of nearness to the precipitation point and the amount of free acid in the liquor.
As the current becomes stronger with the increase of free acid, there is deposited upon the first compact layer a new stratum of loosely adhering peroxide.
The peroxide adheres firmly to the platinum when the proportion of free acid is small, not exceeding 3 per cent.
For the perspiration contains a free acid, probably lactic or butyric; and when it is suppressed, the secretion of this acid is thrown upon the kidneys, and the urine is rendered more acid than naturally.
In all cases it increases the quantity of free acid in the system, and tends to render the secretions, as the urine, more acid than they were before.
There is in both of them an excess of free acid formed in the system.
But we have now only to regard the gastric juice as containing a free acid.
The advantage gained by dissolving bullion with abundance of free acid in the improved process is so evident that it merely requires to be pointed out.
The above list will hopefully provide you with a few useful examples demonstrating the appropriate usage of "free acid" in a variety of sentences. We hope that you will now be able to make sentences using this group of words.
