58 



THE ABSORPTION SPECTRA OF SOLUTION^. 



OXIDIZATION OF URANOUS TO URANYL SALTS IN SOLUTION. 



Some spectrophotographs have been made of the formation of a uranous 

 salt from a uranyl salt by the nascent hydrogen reduction method. These 

 spectrograms are somewhat unsatisfactory, since there is a considerable 

 amount of gas, opaque residues, etc., formed, and the reduction takes a con- 

 siderable length of time. It is hoped in the future that this reduction may be 

 produced by the action of occluded hydrogen (for example in palladium) that 

 will be liberated on being heated, or by some other method that will not 

 require the addition of other acids or salts. 



The reverse process of the oxidization of uranous salts in solution is a 

 very satisfactory one, and the spectrograms can be photographed very well 

 indeed. This method simply consists in the addition of a small amount of 

 hydrogen peroxide to the uranous solution. The spectrophotography of 

 these reactions, as already mentioned, has furnished an admirable method 

 by means of which the uranyl and uranous bands can be completely separated. 

 Several oxidizing agents have been added to aqueous and alcohol solutions 

 of uranous salts that showed both the water and alcohol bands, in order to 

 see whether there is any selective oxidation. 



OXIDIZATION OF URANOUS CHLORIDE BY HYDROGEN PEROXIDE. 



The first solution of uranous chloride to be oxidized, in order to compare 

 the effect of the presence of acid and of other salts, was that of the very 

 intensely colored solution of uranous chloride formed by reducing an ether 

 solution of uranyl chloride. To one part of this solution were added four parts 

 of water, and this required for oxidization about a one-fourth part of a solu- 

 tion of hydrogen peroxide. A cloudy and semi-transparent precipitate was 

 formed during oxidization. When one part of the ether solution of uranous 

 chloride was added to six parts of concentrated hydrochloric acid, the result- 

 ant liquid contained a cloudy precipitate. The addition of a few drops of 

 hydrogen peroxide clarified the solution, but it required over two parts of 

 hydrogen peroxide before the uranous chloride was completely oxidized. 

 Following are the tabulated results of these experiments: 



Parts 

 uranous 

 chloride 

 solution. 



Parts of solvent added. 



1.0 

 1.0 

 1.0 

 1.0 

 1.0 

 1.0 

 1.0 

 1.0 

 1.0 



1.0 

 1.0 



4.0 water 



6.0 hydrochloric acid. Soluble 



12.0 A1C1 3 in water. Small precipitate. . . . 



6.0 Cone. HNO3. Only partly oxidized. . 



10.0 acetic acid. Precipitate formed 



12.0 ethyl alcohol 



12.0 glycerol 



12.0 methyl alcohol. Precipitate formed. . . 

 12.0 Ca(N0 3 ) 2 in 2H 2 and 3CH 4 0. Pre- 

 cipitate 



90.0 ethyl alcohol 



12.0 water, 4.0 XaC10 4 in water, and HC1. 



Parts 



hydrogen 



peroxide in 



water 

 necessary for 

 oxidization. 



0.6 



2.0 



0.5 

 0.7 

 0.6 



0.4 

 0.6 

 1.5 



A solution of uranous chloride in water was prepared in the usual manner, 

 and made strongly acid by the addition of hydrochloric acid, in order to 



