4 The Philippine Journal of Science ms 



Pure sodium hydroxide was prepared by the following method. 

 Pure metallic sodium freed from oxide, carbonate, and hydro- 

 carbons so far as possible was introduced into a test tube, the 

 bottom of which was connected to a mercury pump by a piece 

 of narrow glass tubing about 3 millimeters internal diameter 

 and from 0.5 to 1 meter long. A slight constriction was made 

 in this tube near the test tube. The end of the test tube was 

 then sealed, and the whole exhausted and warmed to drive off 

 hydrocarbon vapors. After sealing the narrow tube near the 

 pump, the sodium was melted and allowed to flow by gravitation 

 through the constriction, thus filling the tube with pure metallic 

 sodium, the crust of oxide and carbonate being held back. 

 Pieces of this tube were broken off and quickly dropped through 

 the hole of a rubber stopper into a flask of pure water, the at- 

 mosphere over which had been replaced by hydrogen. A rapid 

 current of hydrogen was passing through the flask when it was 

 opened to admit the sodium. After the sodium had dissolved, the 

 flask was opened and quickly substituted for flask D (fig. 1) , the 

 apparatus in the meantime having been freed from any carbon 

 dioxide by a soda-lime tube connected at A and sticks of caustic 

 soda in the flask D. It was found on acidifying, boiling, and car- 

 rying the gases with a stream of hydrogen into barium hydrox- 

 ide solution, forced from a bottle into F, through stopcock G, and 

 thus obtained pure, that no trace of carbon dioxide was evolved 

 from the sodium hydroxide thus prepared. C and E are con- 

 densers for holding back vapors of the boiling liquid. Two 

 experiments were made with such a solution. In the first, about 

 0.5 gram of sodium as hydroxide was allowed to react for fifteen 

 hours at room temperature with a small excess of the ester in- 

 troduced through the funnel B. At the end of this time the 

 solution was acidified with sulphuric acid, boiled, and the vapors 

 passed into the barium hydroxide solution. A slight precipitate 

 of barium carbonate was formed. A second experiment, carried 

 out in the same manner except that the alkali was allowed to 

 react with the ester overnight at 50°, produced a much larger 

 precipitate of barium carbonate. By comparing the volume of 

 this precipitate with precipitates from measured quantities of 

 N/50 NaHCOj solution in tubes of approximately the same 

 diameter, it was estimated to represent 0.3 to 0.5 milligram of 

 carbon dioxide. 



An experiment with 5 grams of the ester and 100 cubic centi- 

 meters of N/10 sulphuric acid showed that the carboxyl group 



