FORM OF THE CONDUCTANCE FUNCTION 75 



TABLE XXIX. 

 CONSTANTS OF EQUATION 11 FOR SOLUTIONS IN DIFFERENT SOLVENTS. 



Solvent Solute m K D AO 



Sulphur dioxide ..... KI 1.14 8.5 X 10' 4 0.403 207. 



Iso-amyl alcohol ____ Nal 1.2 5.85 X 1Q- 4 0.374 7.79 



Propyl alcohol ..... Nal 0.75 38.3 X 10~ 4 0.208 20.1 



Phenol ............. (CH 3 ) 4 NI 1.28 2.3 X 10~ 4 0.69 16.67 



Comparing the ionization in ammonia and sulphur dioxide, in view 

 of the much lower value of the constant K, dilute solutions in sulphur 

 dioxide are ionized to a much smaller extent than are solutions in am- 

 monia. On the other hand, in the more concentrated solutions, the ioniza- 

 tion values again approach each other, since the value of D for sulphur 

 dioxide is relatively large and the value of m is much greater than that 

 in ammonia. The conductance curves of solutions in sulphur dioxide, 

 phenol and amyl alcohol pass through a minimum while that of solu- 

 tions in propyl alcohol resembles the curve for aqueous solutions. 



In the case of a great many solutions whose ionization is relatively 

 low, the limiting value of the equivalent conductance in dilute solutions 

 cannot be determined. Under these conditions, the value of K remains 

 indeterminate. Nevertheless, if the ionization is relatively low, the ap- 

 plicability of Equation 11 may be tested approximately. It is apparent 

 that, when the ionization is low, the constant K becomes negligible in 

 comparison with the term involving the constant D. Also, the value 

 of A becomes small in comparison with that of A , so that for purposes 

 of approximation the value of A may be neglected in comparison with 

 that of A . Under these conditions Equation 11 reduces to the form: 



(12) CA 2 = D A 2 m (CA) 9 

 For the sake of brevity we may write: 



(13) DA 2 m =P. 



If we take the logarithm of both sides of this equation, we obtain the 



linear equation: 



(14) log CA 2 = m log CA + log P. 



In order to test the applicability of the equation to solutions of very low 

 ionization, therefore, it is only necessary to plot the logarithms of the 

 values of CA and of CA 2 , both of which may be obtained from experi- 

 mental data. If the equation holds, the points will lie upon a straight 



