. Journal . hea lor a saturated solution of picric acid in anhydrous•Htr is sensibly devoid of colour; this peculiarity, how-s, is not due to the small amount of substance ini tion, for on adding a trace of water the usual colour develops. It is possible to utilise this facta basis of a test for the presence of moisture in ether; 0 n fact, by colorimetric methods (provided the densityd i not exceed 0-725) to estimate approximately thea unt of water present. At a specific gravity of 0 ■ 725t intensitv of the coloration appears to reach a maximum. —W. H. L. 1 nic Acid and its Salts; Gas
. Journal . hea lor a saturated solution of picric acid in anhydrous•Htr is sensibly devoid of colour; this peculiarity, how-s, is not due to the small amount of substance ini tion, for on adding a trace of water the usual colour develops. It is possible to utilise this facta basis of a test for the presence of moisture in ether; 0 n fact, by colorimetric methods (provided the densityd i not exceed 0-725) to estimate approximately thea unt of water present. At a specific gravity of 0 ■ 725t intensitv of the coloration appears to reach a maximum. —W. H. L. 1 nic Acid and its Salts; Gasometric Valuation||—-. M. Wegner. Zeits. anal. Chem., 1903, 42 : and 7], 427—431. F!mic acid is decomposed by concentrated sulphuric acidill water and carbou monoxide. The amount of formicM in sodium formate may be determined by theft) wing method based upon this reaction :—2 of aHot cent, solution of the salt to be examined are placedid:e flask I., shown in the illustration. The tube of the. Jffl& lannel is previously filled with water up to the tap,»Bt the bulb of the funnel contains about 30 of00 -titrated sulphuric acid. The flask II. acts as a dryingW 40 of concentrated sulphuric acid being placedThis second flask is connected to a removing all air from the apparatus by means of aQUI at of carbon dioxide, the acid in the second flask being • e same time heated to 180° C., the acid in the funnel • i >wed to run on to the formate solution in I. At thelp the reaction, this flask is also warmed to 180 C, anvubon dioxide further passed through the apparatus toMp all carbon monoxide into the nitrometer. The formicWijjis not completely decomposed in the first flask, and»n; loisture collecting in the tube between the flasks must be driven over by the aid of a small Same. Traces offormic acid which escape with the moisture from the firstflask are thus decomposed in the second. The percentageof sodium formate is found from the volu
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectchemist, bookyear1882
