IN ETHYL ALCOHOL. 77 



DISCUSSION OF RESULTS. 



It will be noted in tables 23 and 24 that 1, 2, 4 dinitrobenzoic acid 

 shows irregularity in titration values. The conductivity of this acid 

 was determined before we began to keep the solutions used in titrating 

 at a constant temperature. With all other acids the results show that 

 with increase in time a greater amount of esterification has taken place; 

 that is, the normality of the acid has become less. The amount of 

 ester formed in a given time depends upon the nature of the acid. 



Since each dilution was made up independently of the others, that 

 is, by direct weight, it is interesting to note that the proportion of 

 ester formed in the less dilute solutions is much greater than in the more 

 dilute. Indeed, in some cases there is practically no ester formed in 

 the y^-g and -5^- solutions. 



As has already been stated, none of the conductivities is greater than 

 unity; and, consequently, the molecular conductivity of the alcohol for 

 each dilution is relatively quite large, the correction for this factor being 

 in some cases as much as 70 per cent of the total conductivity. It can 

 be seen from the tables that the conductivity of the alcohol alone varies 

 considerably, usually increasing appreciably with time. Some of the 

 conductivities of the alcohol increase with rise in temperature, some 

 actually decrease, while others remain very nearly constant. We can 

 offer no explanation for this lack of uniform variation, except to call 

 attention to the several factors which might affect the conductivity 

 of the pure solvent. One might be the absorption by the alcohol of 

 traces of various gases or water- vapor from the atmosphere. This, 

 however, ought to be a negligible factor, since our cells were very nearly 

 filled and were tightly closed with ground-glass stoppers. 



The decomposition effects brought about by the platinum electrodes 

 may be an important factor. (Compare here the work of Wildermann 

 and others on this question.) It is evident that the electrodes do have 

 some effect, since fresh alcohol just taken from the bottle does have a 

 fairly uniform conductivity. Part of the effect with alcohol which 

 stood in the cell over night might be due to the solubility of the glass 

 cells. This, however, is not at all probable, since our cells have been 

 in constant use in this laboratory for three years, and hard glass is not 

 very soluble in alcohol. 



The conductivities of some of the solutions, and curiously enough of 

 the more dilute solutions, vary to a much smaller extent, with time, 

 than does the conductivity of the pure alcohol. 



It will be recalled that Wakemann plotted curves of conductivity of 

 the organic acids against percentage alcohol (see fig. 21), and on extend- 

 ing the curves in the direction of 100 per cent alcohol they apparently 

 approached zero conductivity as a limit. As can be seen from our 

 results, the conductivities do not actually approach zero, but a number 

 less, and usually very much less than unity. 



