106 ONT THE CALCULATION OF THE CONDUCTIVITY OF 



mixture, the above equations express the conditions which must 

 be fulfilled that there may be equilibrium between the dissociated 

 and unrlissociated portions of each electrolyte, both in the part 

 of the mixture occupied by it and throughout the whole volume 

 of the mixture. The result : 



in a l N x n a a N 2 



V. ~^a~ 



states that in a mixture of solutions of two electrolytes which 

 have a common ion, and are in a state of equilibrium, the con- 

 centration of the ions of the respective electrolytes per unit, 

 volume of the portions of the mixture occupied by them, must 

 be the same. 



With the aid of this result we can find the ionisation co-effi- 

 cients of the constituents of mixtures such as Bender 

 examined. For if v\ and v\ are the volumes of the constituent 

 solutions before mixing, and n l} n 2 the numbers of gramme- 

 molecules per unit of volume which they contain, it gives us the 

 equation : 



1 



We have also 



v l +v 2 = p (v^ + v^) ....... (2) 



and as the co-efficients of ionisation are functions of the 

 dilution only, at constant temperature, we have 



(4) 



Of the quantities involved in these equations, n lt n 2 , v^, v^ 

 are known, and p may be determined by density measurements 

 before and after mixture. The form of the functions in (3) and 

 (4) may be determined if measurements of the conductivities of 

 sufficiently extended series of simple solutions of the constituent 

 electrolytes are made. We have thus four equations with but 

 four unknown quantities. 



