166 Conductivities and Viscosities in Pure and in Mixed Solvents. 



DISCUSSION OF RESULTS. 



The figures in the column marked "Increase over S of KC1" mean 

 the increase in specific conductivity caused by the amount of the added 

 salt in question, over the specific conductivity due entirely to the potas- 

 sium salt. The figures in column marked " Increase over S of 0.6951m 

 CaCl 2 " mean the same with reference to the solutions of calcium 

 chloride, isochloric with the potassium chloride. The last column 

 contains the difference between the values in the two columns just 

 mentioned. It is to be noticed, in all the cases studied, that the 

 increase in conductivity is greater in the case of the potassium chloride. 

 The increase for the last three added salts is about the same. What 

 does this mean? 



The driving back of the dissociation, due to the anions of the iso- 

 chloric solutions, is the same in both cases; a necessary consequence of 

 the solutions being isochloric. Other things being equal, it would be 

 expected that the increase in conductivity would be the same in the 

 two solutions; since the conductivity is a measure of the dissociation. 

 How can the above facts be explained? 



We have a tentative explanation which is by no means final. When 

 a salt is added to water or to the solution of another salt, the added 

 salt is dissociated by the water present. We believe that the combined 

 water, in the solution of hydrated salts, is less associated than the free 

 water, in which case the added salts would be less dissociated; since 

 the dissociation power of a solvent changes with its own association. 

 And further, this effect would be greater the greater the concentration, 

 since more combined water would then be present in the solution of 

 calcium chloride. This seems to be in accord with the facts established. 



These results and conclusions are to be regarded as preliminary. 

 Viscosity undoubtedly plays a role, especially in the more concen- 

 trated solutions. The atomic volume and the velocities of the ions 

 also must be taken into account. 



Taking all of the factors into consideration, these results render 

 highly probable the conclusion that the dissociating power oj combined 

 water is less than that of uncombined water. 



In conclusion, we would thank Dr. E. J. Shaeffer, who, as the result 

 of his spectroscopic investigations in this laboratory, suggested the 

 study of this problem. 



