UNIVERSITY OF VIRGINIA PUBLICATIONS 



BULLETIN OF THE PHILOSOPHICAL SOCIETY 



SCIENTIFIC SECTION 



Vol. I, No. 23, pp. 477-512 October, 1914 



INFLUENCE OF THE CONCENTRATION OF POTASSIUM 



IODIDE ON THE RATE OF DIFFUSION OF IODINE 



IN POTASSIUM IODIDE SOLUTION.* 



BT 



STERLING H. DIGGS. 



The purpose of this work was to discover, if possible, why the con- 

 centration of potassium iodide should affect the rate of solution of metals 

 in iodine, the concentration of the latter being constant. 



This fact, that the concentration of potassium iodide does influence 

 the reaction, had been estabhshed by the work of Van Name and Edgar, 

 and was in a way a serious objection to the "Diffusion Theory of Reaction 

 Velocity," which their work in all other respects confirmed. 



The following is a brief outline of the present work: 



Part I. 



The diffusion theory of reaction velocity, What it is and why it was advanced. 

 Pakt II. 



Determination of the rate of diffusion — Apparatus used by Stefan and Oholm — 



Modification used by Edgar — App^aratus used in this work — Advantages and 



disadvantages. 



Mathematics involved — Solution of the differential equation. 



Complete solution for the present case. 

 Part III. Experimental Data. 



Diffusion of iodine in solutions of potassium iodide of varying concentrations — 



Viscosity of potassium iodide solutions — Density of potassium iodide solutions 



Curves. 



* A dissertation presented to the faculty of the University of Virginia as a part 

 of the requirements for the Degree of Doctor of Philosophy. Read before the scien- 

 tific section of the Philosophical Society at its regular meeting March 23, 1914. 



477 



