CONDUCTION PROCESS IN ELECTROLYTES 27 



lyte having a cross-section of 1 sq. cm. and a length of 1 cm. The spe- 

 cific conductance is a function of concentration, increasing, in general, 

 with increasing concentration. However, in the case of certain electro- 

 lytes at very high concentrations, the specific conductance passes through 

 a maximum. This is the case, for example, with sulphuric and hydro- 

 chloric acids dissolved in water, as well as with certain other electro- 

 lytic solutions. 



The specific conductance, however, is a quantity which is not well 

 adapted to the purpose of comparing the conductance of different electro- 

 lytes. In the case of this property, as in that of many others, it is ad- 

 vantageous to refer the numerical values to equivalent amounts of the 

 dissolved electrolyte. If, therefore, the conductance of a given electro- 

 lyte at two given concentrations is to be compared, the specific con- 

 ductance is divided by the equivalent concentration. This quantity is 

 called the equivalent conductance. As stated above, the specific con- 

 ductance is referred to a unit cube of the electrolyte; that is, to a cube 

 having a length of 1 cm. and a cross-section of 1 sq. cm. In order to 

 avoid unnecessary factors in the expression for the equivalent con- 

 ductance, it is desirable to express the concentration of the electrolyte 

 in equivalents per cubic centimeter, rather than in equivalents per liter. 18 

 In what follows we shall employ the Greek letter j\ to express the con- 

 centration in equivalents per c.c., while the letter C will be employed to 

 express the concentration in equivalents per liter. We have therefore 

 lOOOi] = C. If we represent the equivalent conductance by the Greek 

 letter A, and the specific conductance by the Greek letter \L, then we 

 obviously have: 



> : *-$ 



The value of the equivalent conductance A measures, in fact, the 

 conducting power of the electrolyte in a solution of a given concentra- 

 tion. Suppose, for example, that one equivalent of electrolyte were con- 

 tained between two electrodes 1 cm. wide, separated by 1 cm., and of 

 indefinite extent vertically. If the entire electrolyte were contained in 

 1 cu. cm. of liquid, then the equivalent conductance would obviously be 

 equal to the specific conductance at this concentration, which is unity. 

 If, now, more solvent were added to this solution, the amount of solute 

 remaining constant, the concentration of the solution would be decreased. 

 At the same time there would be an increase in the electrode area, but 

 the total amount of conducting material between the electrodes and the 



Kohlrausch and Holborn, "Leitvermogen der Elektrolyte," 1898, p. 84. 



