POTASSIUM IODIDE. 



95 



noticed, however, that the 

 solution had a high colora- 

 tion, which deepened on 

 standing. Moreover, there 

 was a slight deposit formed 

 at the same time. On evapo- 

 ration the residue was still 

 colored. The strongest solu- 

 tions of the sodium iodide, 

 in acetone, gave a test for 

 iodine with starch paste, 

 while the more dilute solu- 

 tions, though still somewhat 

 colored, gave none. Free 

 iodine was then added to 

 pure acetone until the same 

 color was reproduced. This 

 solution, tested with starch 



140- 

 130- 

 120- 

 110- 

 100- 



'> 90- 



'3 

 o 



- 80- 

 o 



| GOJ 

 "o 

 ^ 50- 



40 

 30- 

 20- 

 10- 



120- 



.110 



100 



FIG. 30. CONDUCTIVITY OF POTASSIUM 



IODIDE IN MIXTURES OF ACETONE AND 



ETHYL ALCOHOL AT 0. 



FIG. 31. CONDUCTIVITY OF POTASSIUM 



IODIDE IN MIXTURES OF ACETONE AND 



ETHYL ALCOHOL AT 25. 



; 50 $ 



Percentage of Acetone 



paste, gave no test for io- 

 dine. Time did not permit 

 the further investigation of 

 this interesting point. 



CALCIUM NITRATE. 



The calcium nitrate used 

 was an anhydrous preparation 

 obtained from Kahlbaum. 

 It was heated for several 

 days at 140, until it had 

 a constant weight. Subse- 

 quently, it was dried for 

 some time at 140 after each 

 exposure to the air. The 

 salt contained no calcium 

 oxide after heating, and 

 showed no appreciable im- 

 purity by the flame test. 



25$ 50^ 



Percentage of Acetone 



100^ 



