OTHER PROPERTIES OF ELECTROLYTIC SOLUTIONS 289 



these solutions is much smaller than in water. Numerous experiments 

 have therefore been carried out in methyl and ethyl alcohols. 



In the following table are given values of the esterification constant 

 for different acids in methyl alcohol, according to Goldschmidt and 

 Thueson, 11 at 25. The numerical values for 0.05 HC1, 0.1 picric acid 

 and 0.1 trichlorobutyric acid are given in the second, third and fifth 

 columns respectively, while in the fourth and sixth columns are given 

 the values for picric acid and trichlorobutyric acid of the strength given 

 in the presence of 0.15 picrate and 0.1 butyrate respectively. 



TABLE CXVI. 



ESTERIFICATION CONSTANTS IN METHYL ALCOHOL FOB DIFFERENT ACIDS 

 IN THE PRESENCE OF OTHER ACIDS AS CATALYZERS. 



Catalyzing acids 

 Esterifying acid HC1 C 6 H 3 N 3 7 Picrate C 4 C1 3 H 6 2 Butyrate 



Phenylacetic acid . . 2.23 0.265 0.047 0.0167 0.00102 



Acetic acid 4.86 0.590 0.100 0.0375 0.00172 



n-Butyric acid 2.23 0.277 0.0535 0.0177 0.00097 



i-Butyric acid 1.55 0.196 0.0353 0.0129 0.00074 



i-Valeric acid 0.583 0.0735 0.00144 0.00475 0.00029 



From this table it may be seen that the catalytic action of an acid 

 is the greater the stronger the acid. Nevertheless, the catalytic action 

 of an acid is not proportional to the concentration of the hydrogen ion. 

 The ratio between the velocity constants for 0.05 N hydrochloric acid 

 and 0.1 N picric acid varies between 7.78 and 8.91 for the different acids, 

 while the ratio of the ion concentrations is 6.56. So, also, the ratio of 

 the hydrogen ion concentrations for 0.1 N and 0.01 N picric acid is 3.64. 

 The ratio of the esterification constants between these concentrations is 

 3.90. It will be observed that, on the addition of sodium picrate to picric 

 acid, the velocity constant varies approximately in the ratio of 1 to 6, 

 while, on the addition of trichlorobutyrate to butyric acid, the velocity 

 constant changes in the ratio of 1 to 18. It should be stated in this con- 

 nection that the values given for the constants of picric acid and tri- 

 chlorobutyric acid in the presence of other salts represent practically the 

 minimum limiting values which are independent of the concentration of 

 the added salt. In other words, the salt added is sufficient to completely 

 repress the ionization of the acid. Accordingly, the residual catalytic 

 action of the acid must either be due to the un-ionized molecule or to 

 some other agency. The weaker the acid, the smaller, relatively, is the 



"Goldschmidt and Thueson, Ztschr. f. phya. Chem. 81, 30 (1913). 





