132 



WORK OF E. G. MAHIN. 



The results obtained by Jones for the molecular weight of cadmium iodide in 

 acetone are given in table 102 and are shown graphically in fig. 59. The molecular 

 weight is 364, while the molecular weight found in a 0.09 normal solution in acetone 

 is 448. Considerable polymerization is thus indicated. 



Table 102. Molecular Weight of Cadmium Iodide in Acetone. 



SUMMARY. 



The work of others has shown that the general law which correlates conductivity 

 and viscosity fails in the case of lithium nitrate, lithium bromide, cobalt chloride, 

 and calcium nitrate, when dissolved in mixtures containing acetone as one of the 

 components of a binary solvent mixture. This is made evident by the abnormally 

 low values for conductivity of these substances in acetone, and it was thought that 

 it might be due to association of the salt in acetone. Determination of conductivity 

 at high dilutions has shown that lithium nitrate, when completely dissociated, is no 

 exception to the rule that molecular conductivity varies inversely as the viscosity; 

 and boiling-point measurements have shown that, at ordinary concentrations, the 

 salt is associated in acetone to a considerable extent. 



Cadmium iodide had already been found to be associated in acetone, and further 

 work on its conductivity in mixed solvents has shown that its behavior is similar to 

 that of lithium nitrate. 



The temperature coefficients of conductivity of lithium nitrate are of about the 

 same order of magnitude as the temperature coefficients of fluidity, though generally 

 somewhat smaller, except at high dilutions. This might be expected from the fact 

 that dissociation is less at 25 than at 0. This influence of temperature is seen 

 more clearly in acetone solutions of cadmium iodide, which have negative temper- 

 ature coefficients of conductivity below a dilution of 0.0001 normal. 



Similar investigations are in progress, having to do with solutions of the other 

 salts mentioned above. 



