The velocity of light Volume 9, no. 1 - Tapa blanda

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1903 edition. Excerpt: ...The necessary amount of barium chloride solution was first brought into an 80 cc. flask, then the measured volume of standard alkali was added, and finally 10 cc. of the carbonate solution was run into this directly from the pipette. When two or three analyses of the same solution were to be made the flasks were all charged with the barium chloride and standard alkali, and corked. Then the carbonate solution was measured from the pipette into each flask with as little loss of time as possible. After mixing, the flasks were tightly closed with rubber stoppers and allowed to stand a few minutes, after which the excess of alkali was titrated with decinormal hydrochloric acid. The net amount of alkali used (that is, the whole amount added less that neutralized by acid in the final titration) is a measure of the carbon dioxide in excess of that existing as normal carbonate. In three determinations, using in each 9.90 c.c. of a bicarbonate solution, there were required, in each analysis, exactly 10.60 c.c. of the standard barium hydroxide solution. In three other determinations, using in each 9.90 c.c. of a different bicarbonate solution, there were required 10.42, 10.42, and 10.40 c.c. of barium hydroxide. By working in the manner just described, no carbon dioxide could be lost by the bicarbonate solution in the course of the analysis, and practically none absorbed from the air by the standard alkali. »i Ze.Uclir.f. anorg. Chemie, Vol. XIII (1897), p. 127. Carbon dioxide may readily be lost during analysis from solutions rich in bicarbonate, if care be not taken to render them alkaline at once. Low results were invariably obtained when, instead of working in the manner described, the bicarbonate solutions were measured into beakers and allowed to...