196 Scientific Proceedings, Royal Dublin Society. 



The production of all the actual products of the reaction, 

 namely, silver iodide, diethyl ether, nitric acid, ethyl nitrate, 

 and ethylene, can be plausibly explained by Nef's dissociation- 

 hypothesis. According to this view, the reactivity of the alkyl 

 iodides in alcoholic solution must be intimately associated with the 

 velocity and extent of this dissociation. 



In order to get exact data bearing on this interesting subject, 

 an extended kinetic investigation of the velocity of the above 

 reaction has been carried out by Miss K. A. Burke and the author. 1 

 The method of experimenting was briefly as follows : — Solutions 

 of silver nitrate and of the alkyl iodide in dry alcohol were made 

 up of the desired concentration and separately warmed in a 

 thermostat. At a given moment the two solutions were mixed, 

 and the resulting solution distributed over a number of small 

 Erlenmeyer flasks contained in the same thermostat. At a given 

 moment, the reaction was stopped in the flasks 2 by running in a 

 measured excess of a solution of ammonium thiocyanate of known 

 strength, It was an easy matter then to determine the amount 

 of dissolved silver nitrate present in any flask at the moment the 

 reaction was stopped, by titrating back the excess of thiocyanate 

 with a standardised silver nitrate solution. 



Working with equivalent solutions of alkyl iodide and 

 silver nitrate, and denoting the common equivalent (in this case 

 molecular) concentration by c, the reaction was found to be 

 bimolecular, i.e., it was found in any given case to obey the 

 velocity- equation : — 



do 



- it ■ u ~- 



The following example exhibits the constancy of k, the 

 " velocity-coefficient," as calculated from the integral formula, 



= 1 /l _ V\ m 



t \c cj 



1 The technical details of this work will be published elsewhere. 

 3 The flasks were covered with black paper during the course of the reaction between 

 the alkyl iodide and silver nitrate. 



