(69) 



increase of pressure (ook place which would indicate tliat the reaction 

 COj -|- C = 2 CO was proceeding. 



The experiment removed all doubt as not only an increase of 

 pressure be could very plainly demonstrated, amounting after a few 

 hours to several cm. of mercury, but after exhausting the apparatus 

 a quantity of CO could be detected in the gaseous mixture which 

 accounted for the observed increase of pressure. 



Contrary to Boudouard's results we have therefore found that the 

 reaction 2 CO — CO^ -f C is reversible at 445°. 



The reason why fairly concordant constants were obtained during 

 the first 15 minutes although no notice had been taken in the 

 calculation of the reversal of the reaction, is simply that the e([uation 



dx .^' 

 -^k,{A-x)-K-^) (1) 



differs but ver}' little from 



^-^ = k,{A-.x) (2) 



at 



A\dien k or x or both are very small, k^ is very small at 445° and 



this is the reason why at first the second equation is satisfied, x 



being then not yet large. 



By means of the first equation we might be able to calculate k 



k, 

 if we knew the equilibrium constant K=:—. 



As analysis seemed to us less accurate we have endeavoured to 

 determine K in the following manner : 



The reaction vessel was filled again with CO, while the time 

 was noted which elapsed between the filling and the first reading 

 so as to be able to find the starting pressure by extrapolation. The 

 heating at 445° was now continued until the pressure after the lapse 

 of some hours did not undergo any further change. 



K could then be calculated from the pressure at the start and at 

 the finish. 



To decide whether tlie final pressure corresponded with a real 

 conditicm of ecpiilibrium, the same ex])eriment was repeated starting 

 with CO.. If the first final condition had l)oe]i a real e(|uilibrinm, 

 the same value ought now to be found for K. 



Up to the present we found this by no means to be the case but 

 \ve do not at all consider the research tiuished in this direction. We 



1) It is faken for grnntod licre that the reaction GOo + C — 2 CO is also a 

 unimolecular one. 



