RATE OF DIFFUSION OF IODINE IN KI 509 



1. It has been shown that the rate of diffusion of iodine in KI solution 

 increases with the concentration of the potassium iodide, as was antici- 

 pated from the results of reaction velocity experiments performed by Van 

 Name and Edgar. 



2. Determinations of the density and viscosity of KI solutions were 

 made for the following concentrations, 0.125 n, 0.25 n, 0.50 n, 1 n, 1.50 n 

 and so on up to 5 n. 



3. Curves have been drawn showing the relation of fluidity (viscosity), 

 density, and diffusion, to concentration of potassium iodide, and to each 

 other. 



4. A comparison has been made with some other well known salts, 

 and curves to illustrate this have been drawn. Also an empirical ex- 

 pression has been found to express approximately the relation between 

 the fluidity, densitj', and diffusion, for our present case, i.e., iodine in KI 

 solution. 



5. The diffusion theory of reaction velocity in general, and the work 

 of Van Name and Edgar in particular, has been completely confirmed, 

 in so far as the disturbing effect of increased concentration of KI is con- 

 cerned. 



For aid, assistance, encouragement, and guidance, always freely given, 

 the writer wishes particularly to thank Prof. Graham Edgar, under whose 

 direction and with whose assistance the work was done. He also wishes 

 to thanlf Prof. L. G. Hoxton and Prof. C. M. Sparrow for many hints 

 and for encouragement in performing the work. 

 University or Virginia. . 



March 18, 1914. 



REFERENCES. 



(1) Noyes and Whitney, 1897. Concept of the unstirred layer on the surface of 



the solid in the case of heterogeneous reactions. Zeitschrift fur physik- 

 alische Chemie, xxiii, 689. 



(2) Nemst, 1911. The unstirred layer as in (1) above. Theoretical Chemistry — 



English translation, 584, etc. 



(3) Nemst and Brunner, 1904. The unstirred layer as in (1) and (2) above. Zeit- 



schrift fur physikalische Chemie, xlvii, 52 and 56. 



(4) Ericson-Auren and Palmaer, 1906. Claims that the temperature coefficient 



of reaction velocity bears no relation to the temperature coeflBcient of 

 diffusion, and that therefore the diffusion theory of reaction velocity 

 can not be sound. Zeitschrift ftir physikalische Chemie, Ivi, 696. 



