( 72 ) 



We must say a few words about their plausible explanation of 

 the change from a uidmolecular to a himoïecuïar course, wliich 

 thej thought they had discovered. 



After having made the same supposition as we did for the uni- 

 molecular course namely 



I. CO == C + 

 II. CO + = CO, 

 the}" say: 



,/Der Dissociation des Kohlenoxydes in seine Elemente wiirde dann 

 ein Oxydationsvorgang folgen. Spielt sich der letztere, ^vie bei dem 

 Sauerstoff im status nascens zu erwarten ist, mit sehr grosser Ge- 

 schwindigkeit ab, welche die Dissociationsgeschwindigkeit übertrifFt, 

 so findet man eine monomolekulare Reaction. Steigt bei höherer 

 Temperatur die Geschwindigkeit des Dissociationsvorganges verhalt- 

 nissmassig mehr an als die des Oxydationsprocesses, so fallen 

 schliesslich die Vorgange zeitlich zusammen, und wir erhalten den 

 Eindruck einer bimolecularen ,/gekoppelten" Reaction. 



Auf diese Weise lasst sich fur die auffallige Erscheinung eine 

 plausible Erklarung geben." 



But what has been overlooked here is that in order that the 

 reactions I and II shall give the im])ression of a unimolecular 

 reaction, the second must take place with immeasurable velocity. 

 If this is true at a low temperature it is certainly so at liigher 

 temperatures and even if the velocity of the first reaction has in- 

 creased this will be the only one which will be observed so long 

 as it proceeds with measurable velocity. 



We are, therefore, inclined to contend that it is plausible to assume 

 that if the reaction is a uninu)lecular one at a low temperature 

 it cannot be expected that the order of the reaction will increase 

 at a higher temperature. 



Summary of our conclusions: 



1. The transformation of CO into CO, and C is unimolecular 

 for all the temperatures at which we have experimented: 256°, 310°, 

 340'' and 445°. 



2. Contrary to the result obtained by Boudouard the reaction 

 is reversible at 445°, 



3. The equilibrium constant could not be determined, as up to 

 the present, we haA-e found that the same condition of equilibrium 

 is not attained starting from CO and from CO, + C. 



Amsterdam, Chem. Lab. University, May 1903. 



