Tri- Brora ide Equilibria. 



113 









Table V. 















Zinc Iodide. 









1. a = 



0-2135 molar Zr 



1I2 + O-OII 



2. a = 0-1283 molar Znl2 + 0-00104 





molar HI. 







molar HI. 





(21) 



+ (2l3) = 



0-438 molar. 



(21) 



f (213) = 0-2577 



molar. 



h 



g 



c 



K^ 



h 



y 



c 



i^i 



38-48 



76-9 



580 



0-00138 



76-2 



380-4 



607 



0-00131 



32-41 



65-2 



580 



0-00141 



51-0 



195-0 



590 



0-00135 



13-06 



25-09 



579 



0-00141 



22-20 



78-5 



580 



0-00145 



5-69 



11-01 



578 



0-00145 



8-07 



39-55 



579 



(000213) 



2-985 



5-97 



578 



0-00151 



3-591 



11-57 



578 



0-00142 



1-632 



3-171 



578 



0-00147 



1-539 



4-88 



578 



0-00141 



0-643 



1-222 



578 



0-00144 



0-975 



3-164 



578 



0-00145 



0-3451 



0-672 



578 



0-00148 



0-4104 



1-352 



578 



0-00147 



0-25'73 



0-515 



578 



0-00152 



0-2052 



0-830 



578 



(0-00181) 





mean 



0-00145, 





mean 



0-00140^ 





Table VI. 







Table 



VII. 





Lanthanum Iodide. 



a- 0-02179 molar Lais. 



(21) + (213) = 3a = 0-0654 molar. 



6 



28-7 



18-94 



10-29 



5-98 



3-648 



660-0 

 333-0 

 151-5 



80-7 

 47-9 



c 

 650 

 610 

 580 

 578 

 578 

 mean 



^1 

 0-00138 

 0-00139 

 0-00144 

 0-00142 

 0-00144 

 0-00141 



Zinc Potassium Iodide. Znl2.Kl. 

 a— 0-1289 molar Znl2 + 



0-1239 molar KI. 

 (2I) + (2l3)rr 0-3717 molar. 



h 

 45-4 

 24-10 

 10-04 

 7-42 

 3-345 

 1-515 

 0-933 

 0-605 



105-3 

 58-6 

 27-45 

 16-42 

 7-11 

 3-272 

 2-031 

 1-331 



c 

 585 



580 

 580 



578 

 578 

 578 

 578 

 578 



^1 

 0-00130 

 0-00146 

 (0-00171) 

 0-00141 

 0-00137 

 0-00140 

 0-00141 

 0-00142 



mean 0-00139, 



Discussion of Hesults. 



Considering first the results obtained with iodides, as given 

 in Table III to YII, we find two different types of behavior. 

 Strontium iodide, nickel iodide, zinc iodide, and lanthanum 

 iodide behave " normally," that is, they give a value of the 

 equilibrium constant K^ which agrees with the value given by 

 the iodides of the alkali metals. The nickel iodide, zinc iodide, 

 and lanthanum iodide solutions contained a small amount of 

 hydrogen iodide, but since the calculations in the case of both 

 of these solutions were based upon the total iodide concentra- 

 tions, and since hydrogen iodide itself falls in the normal class, 

 it is reasonable to conclude that the presence of this hydrogen 

 iodide can not have had any appreciable effect upon the results. 



This inference is supported by the fact, shown in Table YII, 

 that when zinc iodide and potassium iodide are present together 



