196 PROPERTIES OF ELECTRICALLY CONDUCTING SYSTEMS 



calcium nitrate is obviously of the same order. Even at a dilution of 

 1600 liters, therefore, calcium nitrate is ionized less than 10 per cent. 

 The addition of hydroxy-compounds, which tend to form stable complexes 

 with calcium salts, causes an enormous increase in the conductance of 

 solutions of this salt in acetone, even though the amount of the second 

 component added is relatively small. The curves as drawn are only 

 rough approximations and it is not improbable that the initial conduct- 

 ance increase is even greater than indicated in the figure. Owing to the 

 increased ionization of calcium nitrate on the addition of water, there- 

 fore, the conductance rises enormously, even though the speed of the ions 

 is greatly depressed on the addition of water. As a consequence, the con- 

 ductance curve on addition of water passes through a pronounced maxi- 

 mum at a composition at or above 75 per cent of acetone. On the 

 addition of further amounts of water, the conductance curve follows, 

 roughly, the fluidity curve of the solvent mixture. The addition of 

 methyl alcohol likewise results in an increase in ionization, although this 

 increase is much lower than in the case of water. The conductance curve, 

 therefore, passes through a comparatively flat maximum at a composition 

 in the neighborhood of 25 per cent of acetone. The ionization of calcium 

 nitrate dissolved in a mixture of methyl alcohol and acetone therefore 

 has not reached a value corresponding to that of a normal electrolyte, 

 even when as much as 75 per cent of methyl alcohol has been added. 

 The addition of ethyl alcohol causes a marked increase in the conductance, 

 although considerably less than that due to methyl alcohol. The curve 

 passes through a distinct maximum, after which the conductance de- 

 creases, chiefly owing to the decrease in the fluidity of the mixture. 



At the higher concentration, the curves are greatly modified. Again, 

 the ionization of the electrolyte is greatly increased on addition of the 

 second solvent, as is indicated by a marked increase in the conductance 

 of the solutions. In the case of water, the curve exhibits a marked inflec- 

 tion point in the neighborhood of the composition containing 50 per cent 

 of alcohol and water. At these higher concentrations, therefore, solu- 

 tions of calcium nitrate in mixtures of acetone and water exhibit an 

 ionization much below that of normal electrolytes. The curve, on addi- 

 tion of methyl alcohol, shows a continuous increase in the conductance 

 throughout its course. That for ethyl alcohol shows a slight increase 

 only, the curve exhibiting a very flat maximum. At the higher concen- 

 trations of the salt, therefore, the addition of ethyl alcohol causes only 

 a relatively small increase in the conductance of calcium nitrate. Actu- 

 ally, however, the ionization is considerably increased on the addition of 

 ethyl alcohol, since the fluidity of the ethyl alcohol mixture is much lower 

 than that of pure acetone. 



