48 



VELOCITY OF REACTIONS 



The second table gives the results of an experi- 

 ment on saponification of a concentrated aqueous 

 solution of ethyl butyrate at 35° C. by means 

 of a lipase extracted from lard. q indicates the 

 quantity of non- decomposed ethyl butyrate de- 

 termined by measuring the butyric acid set free 

 after a time of / minutes. The acidity was 

 measured by titration with a solution of barium 

 hydrate. In both tables K represents the value 

 of the constant of velocity of reaction calculated by 

 means of the formula for monomolecular reactions : 



t q 



Katalysis of H 2 Oo at 

 i5°C. 



Saponification of Ethyl 

 Butyrate at 35 C. 



The constant K does not in either case vary 

 more than may be due to experimental errors. 

 The constancy of K in each case indicates that 

 the law for monomolecular reactions is really 

 fulfilled. This is due to the circumstance that the 

 products of reaction do not chemically interfere 

 with the reagents. 



