CONDUCTION PROCESS IN ELECTROLYTES 37 



acids and bases, however, have a markedly higher ionization than the 

 salts. Salts of higher type exhibit a lower degree of ionization than 

 simpler salts. But here, again, salts of the same type have approxi- 

 mately the same ionization at corresponding concentrations. 



If electrolytes approach complete ionization at low concentrations 

 and if the ions in these solutions move independently of one another, 

 then, if the transference numbers of the electrolytes are known, the value 

 of the equivalent conductance of the individual ions may be calculated. 

 If the conductances of a sufficient number of pairs of electrolytes have 

 been determined, it is only necessary to know the transference number 

 of a single electrolyte. In general, the values of the ionic conductances 

 are based upon the transference number of potassium chloride. The 

 values of the equivalent conductances of various ions in water at 18 are 

 given in Table V. 24 



TABLE V. 



EQUIVALENT CONDUCTANCES OF THE INDIVIDUAL IONS AT 18. 



Cs 68.0 Ba 55.4 Cl 65.5 



Rb 67.5 Ca 51.9 N0 3 61.8 



Tl 65.9 Sr 51.9 SON 56.7 



NH 4 64.7 Zn 47.0 C10 3 55.1 



K 64.5 Cd 46.4 Br0 3 47.6 



Ag 54.0 Mg 45.9 F 46.7 



Na 43.4 Cu 45.9 I0 3 34.0 



Li 33.3 La 61.0 S0 4 68.5 



H 314.5 Br 67.7 C 2 4 63.0 



Pb 60.8 I 66.6 Fe(CN) 6 95.0 



The equivalent conductance values of the different ions are of the 

 same order of magnitude, although the values for the hydrogen and 

 hydroxyl ions are markedly greater than for the other ions. This is in 

 agreement with the greater values of the conductance of solutions of 

 the strong acids and bases. The conductance values of the different ions 

 appear to bear no simple relation to their constitution. So, for ex- 

 ample, lithium, which is lighter and has a smaller atomic volume than 

 the remaining alkali metals, has the lowest conductance of any of the 

 ions whose conductance values are tabulated. On the other hand, the 

 nitrate and the chloride ions have markedly higher values than the 

 fluoride ion. 



5. Molecular Weight of Electrolytes in Solution. The hypothesis of 

 Arrhenius, that the ionization of an electrolyte may be measured by the 



"Noyes and Falk, loc. cit. 



