RATE OF DIFFUSION OF IODINE IN KI 



481 



The following sample table taken from the work of Van Name and 

 Edgar will serve to illustrate the high degree of accuracy of their work. 



Rale of Solution of Hg in Iodine. 

 At S5°. 



100 grams KI to the litre, rate of stirring 170. 



Collecting all of the constants obtained by Van Name and Edgar for 

 a given rate of stirring (say 240) we have the following table: 



Hg 400 grams KI per litre 10. 



Cu 9.98 )• mean, 10. 13 



Ag 99.93 



Hg 200 grams KI per litre 9.55 



Cd 9.56 \ mean, 9.58 



Zn 9.64 



Hg 100 grams KI per litre 8.81 



Cd 8.69 f- mean, 8.71 



Zn 8. 



In the above tables c represents the concentration, At the time interval, 

 V the volume of the solution, and k the reaction velocity constant. There 

 are three points to be particularl}^ noted: 



1. That the results are of high order of accuracy for this kind of work, 

 and that therefore we can put more rehance in the results than we can in 

 the rather uncertain results of previous investigators. 



2. That the reaction velocity constant is approximately the same for 

 all metals used, and that this "constant" increases very decidedly with 

 increase of the -potassium iodide. 



3. That the reaction velocity constant increases, as was to be expected, 

 wath the rate of stirring. 



