Volumetric Estimation Of Phosphoric Acid

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1882 edition. Excerpt: ... of liquid shall contain 0-1 gm. P3O3, which is about the proportion that would naturally occur in the usual course of analysis. Standard Phosphoric Acid corresponding volume for volume with Standard Uranium.--This solution is obtained by dissolving 1471 gm. of microcosmic salt in a liter, and is two and a half times the strength of the solution before described; it is used for residual titration in case the required volume of uranium is overstepped in any given analysis. A little practice enables the operator to tell very quickly the precise point, but it must be remembered that when the two drops are brought together for the production of the chocolate colour, however faint it seems at first, if left for some little time the colour increases considerably, owing to the retarding action of the sodic acetate and acetic acid upon the formation of uranic ferrocyanide, but this has no effect upon the accuracy of the process, since the original standard of the solution has been based on an experiment conducted in precisely the same way. TKt Analytical Process: In estimating unknown quantities of phosphoric acid, it is necessary to have an approximate knowledge of the amount in any given material, so as to fulfil as nearly as possible the conditions laid down above; that is to say, 50 c.c. of solution shall contain about O-l gm. P. or whatever other proportion may have been used in standardizing the uranium solution. It is found that considerable variations in the amount of sodio acetate and acetic acid modify the ending of the process to a noticeable extent; on the other hand, if the operation be conducted with approximate volumes of liquid and amounts of substance very concordant results are obtained, and I dp not hesitate to say that with...