INTRODUCTION. 9 



and equal to about 0.7. Water and glycol are exceptions, giving products equal 

 to 1.0 and 1.32, respectively. The product noo-rj is also independent of temperature. 

 Therefore, generally speaking, conductivity varies as the fluidity of the solvent. 

 But, as we have shown, in certain solutions containing acetone this relation no 

 longer holds. 



It may further be noted that Jones has shown 1 that cadmium iodide and ammo- 

 nium sulphyocyanate, in acetone solutions, have abnormally high molecular weights, 

 although such solutions conduct the current. He pointed out that these facts indi- 

 cate simultaneous association and dissociation of the solute; a high concentration 

 of molecular complexes, which causes an abnormal apparent molecular weight, co- 

 existing with a low ionic concentration, which causes a low conductivity value. A 

 consideration of these points suggested to Jones and Mahin 2 several lines of inquiry, 

 which were taken up by them. They sought to answer the following questions: 



1. Will those salts that have, at ordinary concentration, abnormally low values 

 for molecular conductivity, possess, when completely dissociated, values which are 

 inversely proportional to the coefficient of viscosity? 



2. If so, is the product of molecular conductivity and viscosity constant for 

 mixed solvents and at different temperatures? 



3. Is the value of the constant the same for different electrolytes? 



4. Are the abnormal conductivities in acetone and mixtures of acetone with other 

 solvents clue to association of the salt? 



The first salt studied was lithium nitrate. Extreme precautions were taken to 

 insure purity of the solvents, and measurements were carried to dilutions as high 

 as 200,000 liters wherever practicable. Under these conditions the conductivity 

 curves assumed forms which differed markedly from those obtained for dilutions 

 between 10 and 1,600 liters, and which closely resembled the fluidity curves. More- 

 over, the product of the viscosity coefficient and the maximum conductivity in 

 solutions of acetone mixed with the alcohols has a mean value of 0.62, agreeing well 

 with Walden T s value of 0.70 for simple solvents/and being independent of tempera- 

 ture. With acetone-water mixtures, the product varies between 1.00, the value for 

 water, and 0.63, the value for acetone. 



Some determinations of the molecular weight of lithium nitrate in acetone by 

 the boiling-point method brought out interesting results. The concentration of 

 the solutions varied roughly between normal and tenth-normal. Even in the more 

 dilute solutions the indicated molecular weight was 83.1, while the value required 

 by the formula LiN0 3 is 69.07. This accounts for the low conductivity of lithium 

 nitrate in acetone solutions of not very great dilution. 



As already stated, cadmium iodide was found by Jones to be associated in acetone, 

 and a study of this salt was next made. Results in this case were not so satisfactory 

 as with lithium nitrate. The conductivity curves show signs of regaining a simi- 

 larity to the fluidity curves, but the resemblance is not so close as with the other 

 salt. Moreover, the product of the viscosity by the maximum conductivity is 

 irregular. The conductivity data show that in most cases a limiting value was not 

 reached with cadmium iodide, and some solutions more nearly approached the true 



'Amer. Chem. Journ., 27, 16 (1902). 'See "Work of Mahin" in this monograph. 



