114 



Studies on Solution. 



difference, and the conductance of the aromatic compounds seems to be 

 independent of the position of the various substituent groups. Sodium 

 picrate has a much larger conductance than any other salt, and the 

 monosodiumsulphosalicylate at high dilutions gives abnormally large 

 and increasing conductance values, due probably to the secondary 

 ionization of the carboxyl group at these high dilutions. 



In discussing the temperature coefficient of conductance it is to be 

 noticed that this value becomes gradually larger with increase in 

 dilution, and at the highest dilutions approximates the value 0.0200. 

 Just as in the conductance results, there is here no definite relation 

 between the values for the temperature coefficient and chemical 

 composition. 



It is of importance to note that this work on the sodium salts of 

 the organic acids in absolute alcohol has been greatly restricted, owing 

 to the almost complete insolubility of a great many of these salts in 

 this solvent. If the work were carried out in alcohol which was not 

 absolute, practically all the salts could be studied, for it is necessary to 

 add only a very small amount of water to obtain a sufficient degree of 

 solubility. We have approximately covered the field of available 

 compounds. It is of interest to note that the polybasic acids of both 

 the aliphatic and aromatic series are excluded from study for this 

 reason, as well as all unsaturated acids of both series. A number of 

 salts of aromatic acids with di- and tri-substitutions in the ring were 

 likewise impossible to study. 



Reference has already been made (see pages 100-103) to the work 

 of Heinrich Goldschmidt on the conductance of alcoholic solutions of 

 sodium salts. We have purposely investigated most of the salts which 

 he studied. A comparison of these results is conveniently made by 

 reference to the following tables : 



It can be seen from these tables that the two series of conductance 

 values are in accordance, but an exact comparison can not be made 

 because of the fact that the values of A in the two series refer to some- 

 what different concentrations. In order to make an effective com- 

 parison we have plotted the values of A against the logarithms of the 

 volume V in the case of sodium trichloroacetate (see fig. 26). The 

 points circled refer to the data of Goldschmidt and the crosses to 



