Conductivity of Organic Acids in Ethyl Alcohol. 



129 



increased with increase in the concentration of the water present in the 

 solution. The ju^ values for the weaker acids could not be determined 

 directly, as had been done previously for the strong acids, and Gold- 

 schmidt employed the method of Ostwald for calculating the limiting 

 conductivity of an acid from that of its sodium salt. The values 

 obtained are given in table 73, which shows that the difference in the 

 migration velocities of the anions is very slight. 



From the n x values of the acids, the degrees of dissociation (a) and 

 the affinity constants (k) were calculated. The values of k given in 

 table 74 were obtained for the solutions in absolute alcohol. 



TABLE 74. 



The influence of water upon the values of k was also investigated, 

 with the result that k was found to increase regularly with increasing 

 concentration of water. The law of this increase was expressed in the 

 form of an equation which Goldschmidt deduced from theoretical 

 considerations. 



In conclusion, Goldschmidt showed that the influence of the weaker 

 acids upon the velocity of esterification could be calculated by means 

 of the constant 0.0583. The calculated values agreed very satisfac- 

 torily with those obtained experimentally. 



This work of Goldschmidt has been discussed at some length, not 

 because it is a final word on the subject with which it deals, but for the 

 reason that it presents an excellent illustration of the ever increasing 

 applicability of the conductivity method to the solution of chemical 

 problems. 



EXPERIMENTAL WORK. 



REAGENTS. 



The alcohol used in this investigation was prepared in the following 

 way: Ordinary 95 per cent alcohol was heated for several days with 

 lime in a copper tank provided with a ground-brass stopper and reflux 

 condenser, and then distilled through a block-tin condenser. The 

 product of this distillation was reheated with fresh lime and again 

 distilled, the first and last portions of the distillate being discarded. 



