The British pharmacopœia / published under the direction of the General Council of Medical Education and Registration of the United Kingdom, pursuant to the Medical Act (1858).

Date:: 1885

Credit: The British pharmacopœia / published under the direction of the General Council of Medical Education and Registration of the United Kingdom, pursuant to the Medical Act (1858). Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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$VOLUMETRIC SOLUTION OF OXALIC ACID. (CrystaUised OxaUo Add, HA04,2H„0 = 126.) Take of Oxalic Acid, in crystals . . . 660 grains Distilled Water .... a sufficiency Put the oxalic acid into the 10,000 grain flask, fill the flask to about two-thirds of its bulk with water, allow the acid to dissolve, and then dilute the solution with more water until it has the exact volume of 10,000 grain-measures. Fill a burette with the fluid, and add it gradually to a solution of 10-6 grams of pure carbonate of sodium (which may be obtained by heat- ing the ordinary pure bicarbonate of sodium to redness in a platinum crucible for a quarter of an hour), containing a few drops of solution of Htmus, until the red colour produced ceases to change to blue on boiling. Note the number of grain-measures used {n), then put 9,000 grain-measures of the solution of oxalic acid into a graduated jar, and augment this quantity by the addition of distilled water until it amounts to grain-measures. 1,000 grain-measures of this solution contain half a molecular weight in grains (63 grams) of oxalic acid, and are therefore capable of neutralismg one molecular weight in grains of such alkalies as potash, KHO, or soda, NaHO ; or half the molecular weight in grains of such salts as anhydrous carbonate of sodium, Na2C03, crystalhsed carbonate of sodium (NaoCOa.lOHaO), etc. Grammes and cubic centimetres may be employed instead of grains and grain-measures, but for convenience -^th of the numbers should be taken. 100 cubic centimetres contain ^th. of a molecular weight ui grammes (6-3 grammes) of oxalic acid, and will neutralise -j^th of a molecular weight in grammes of an alkali. The following substances are tested witli this solution :—$