A systematic handbook of volumetric analysis, or, The quantitative determination of chemical substances by measure, applied to liquids, solids, and gases / by Francis Sutton.

Date:
1911
Catalogue details

Licence: In copyright

Credit: A systematic handbook of volumetric analysis, or, The quantitative determination of chemical substances by measure, applied to liquids, solids, and gases / by Francis Sutton. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    ADDENDA AND CORRIGENDA. Page 41. Methyl Red.—The colour changes of Methyl Orange and Methyl Red and the value of the latter as an indicator have been recently discussed by H. T. Tizard.* The author gives a method for the preparation of methyl red which is said to give higher yields than that recommended by Rupp and Loose. The author concludes that methyl red is greatly superior to methyl orange as indicator. Not only is the end-point very much sharper, but the neutral point so found is very much nearer the theoretical point than with methyl orange. Page 142. Determination of Chlorine by M o h r ' s Method.— In the presence of much organic matter, or of sulphuretted hydrogen, the solution may be prepared for titration as follows :— 200 c.c. are warmed to about 100° C. and neutral potassium permanganate solution added in slight excess. After boiling for about five minutes if the colour is destroyed a little more permanganate solution is added. The excess of permanganate is then removed by adding a few drops of alcohol to the hot liquid, which, after standing for 15 minutes, is filtered, and the filtrate when cooled diluted to the original volume. The solution, which must be neutral, is then divided into two equal portions and titrated. Page 154. Antimony. G y o r y ' s Method. J. B. Duncan| recommends the following procedure. He standardizes the ^/lo potassium bromate solution by dissolving 0'3 gm. of pure finely divided antimony in 20 c.c. HCl and a few drops of bromine in a covered 400 c.c. beaker, keeping the hquid warm and occasionally shaking till the metal is dissolved. Then boil off excess of bromine, cool a little, and add about 0-75 gm. of sodium sulphite. Boil the mixture down to about half its volume to drive off SOg. (In the case of alloys this latter operation will also remove any arsenic present.) Rinse the cover and sides of the beaker with, hot water, and add a little HCl. Then heat the liquid to boiling and run in the decinormal bromate from a burette until nearly all the antimony has been oxidized. Now add three drops of methyl orange and continue the addition of bromate until the colour of the methyl orange is destroyed. About 50 c.c. will be required, as 1 c.c. of ^/lo bromate = about 0-006 gm. Sb. The exact value of I c.c. is thus obtained. The process is strongly recommended for the analysis of hard lead, alloys, ores of antimony, etc. 0-3 gm. is taken for the determination, •J. C. S. 1910. 97. 3477-3490. tC. A^. 1907,95, 49. 2 R 2