﻿1 34 BACON. 



No gas collected when the solutions were left standing over night. Both were 

 heated to 100° in the morning and then placed in the sunlight. 



Time. 



(«) 



(6) 



8.30 to 10.00 



0.5 



2.0 



10.00 to 11.00 



.5 



5.0 



The marked falling off in the catatysis with ferric salts may be connected 

 with the formation of a precipitate of ferrous oxalate which soon appears in the 

 solution. 



It would seem probable that the decomposition of oxalic acid takes the 

 course of first evolving carbon dioxide and leaving formif acid and that 

 the latter then breaks down into carbon monoxide and water, but formic 

 acid with uranium acetate as a catalyzer gave no gas. As formic acid can 

 be demonstrated to be present during the catalysis of oxalic acid by 

 uranium salts, its formation is probably due to the reaction : 



CO+H 2 0=HCOOH 



accelerated by uranium salts as a catalyzer. 



The further study of this phase of the reaction is of considerable im- 

 portance both from a theoretical and a practical standpoint. 



Oxalic acid when treated with potassium bichromate, gives off gas 

 even in the dark, but there is no decomposition either in the dark or 

 sunlight with chromic chloride or with copper svdphate. 



Experiment 12. — A study of the decomposition of potassium permanganate in 

 the presence of uranium salts was next undertaken with a solution which contained 

 approximately 4 grams of potassium permanganate per liter. (1 cc=0. 00697 Fe.) 



(a) 25 cubic centimeters potassium permanganate solution 



( b ) 25 cubic centimeters potassium permanganate solution and 



10 cubic centimeters water. 



(c) 25 cubic centimeters potassium permanganate solution, 0.1 



gram uranium acetate and 10 cubic centimeters water. 



The solutions were placed in the sunlight from 11.15 a. m. to 1.05 p. m., 

 then 40 cubic centimeters of ferrous sulphate solution were added to each, by 

 which means all were decolorized, and they were then titrated back with 

 permanganate. 



Number of cubic centimeters of permanganate required: 



(«) (b) (c) 



3.2 3.3 3.3 



Uranium salts therefore have no effect on this reaction. 



It is well known that reactions involving oxidation and reduction are 

 usually very susceptible to catalyzers, and that many substances such 

 as alkaloids, ammonium salts, sugars, etc., act as if they were poisons 

 for the latter; whereas copper and iron salts usually accelerate the rate. 4 



4 Young: J. Am. Chem. Soc. (1902), 24, 301. 



