ELECTROLYTES IN MIXED SOLVENTS 179 



tions of calcium nitrate and sodium iodide in propyl alcohol. In the 

 case of calcium nitrate the values given are the molecular conductances 

 whose limit at low concentration should be approximately twice that of 

 the equivalent conductance. It will be observed that while sodium iodide 

 is highly ionized, calcium nitrate is ionized to only a relatively small 

 extent. 



At a concentration of approximately 10~ 3 molal, the ionization of cal- 

 cium nitrate is less than 15 per cent, whereas at the same concentration 

 sodium iodide is very largely ionized. If the equivalent conductances are 

 plotted against the concentrations, the curve of sodium iodide approaches 

 a limiting form asymptotically, whereas that of anhydrous calcium nitrate 

 is convex toward the axis of concentrations, the increase in conductance 

 being the greater the lower the concentration of the electrolyte. 



The addition of 0.185 mols of water per liter to the calcium nitrate 

 solution, whose concentration was 0.045 N, raised the conductance from 

 0.772 to 2.036, and an additional 0.346 mols raised the conductance to 

 2.991. It is evident, therefore, that the addition of water to a solution 

 of anhydrous calcium nitrate in propyl alcohol causes a large increase 

 in the ionization of the salt. This follows, since the viscosity of the 

 solvent is not materially affected by the addition of small amounts of 

 water. It is true that, if a complex is formed on the addition of water 

 to a solution of calcium nitrate, the speed of the ion may be affected by 

 the addition of water, but it seems likely that, if anything, the speed of 

 the complex will be lower than that of the original ion. However this 

 may be, it is very unlikely that the speed of the complex could vary 

 greatly from that of the anhydrous ion and the resulting change in the 

 conductance must therefore be due to a change in the ionization of the 

 electrolyte as a result of the formation of a complex with water. 



TABLE LXV. 



CONDUCTANCE OF Mg(N0 3 ) 2 .6H 2 IN ANHYDROUS PROPYL ALCOHOL AND 

 IN PROPYL ALCOHOL CONTAINING 0.7 PER CENT WATER AT 25. 



Anhydrous Solvent Solvent + 0.7% Water 



CX10 3 A mo i. CX10 3 A 



0.394 12.422 .298 17.774 



0.865 10.730 1.950 9.062 



1.942 8.932 3.758 7.326 



3.483 7.774 6.339 6.188 



6.406 6.408 11.670 5.096 



9.804 6.026 19.460 4.400 



19.89 4.674 30.410 3.921 



36.12 3.866 49.560 3.555 



