■Section III., ISUli. [ 65 ] Trans. R. S. C. 



V. — On the Calculation of the Conductivity of Electrolytes. 



By Prof. J. G. MacGregor, D.Sc, Dalhousie College, Halifax, X.S. 



(Read May 20, 1896.) 



According to the dissociation theor}- of electrolysis, it is possible to 

 •calculate the conductivity of complex solutions of electrolytes, provided 

 we know the quantities of the electrolytes present in a given volume of 

 the solution, their states of dissociation, and their specitic molecular con- 

 ductivities at intinite dilution. If !• is the volume of a solution which 

 contains j\\, JS^^, JS^.^, etc., gramme-equivalents of the respective electro- 

 Ij'tes present, if a^, a^, o-^, etc., are their coefficients of dissociation or 

 ionisation, and if /x goi, M 0025 /' xs- ^^c, are their specific conductivities 

 per gramme-equivalent at intinite dilution, then, according to the above 

 theory, the specific conductivity of the solution is equal to 



- I a^XjA cc, + a.^X,^i 00., + ^V%/' 003 + etc. j . 



In order, therefore, to effect a calculation we must be able to deter- 

 mine (1) the numbers of gramme-equivalents of the various electrolytes 

 present, (2) their ionisation coeflîcients, and (3) the specific molecular 

 conductivities of the electrolytes at infinite dilution in the circumstances 

 in which they exist in the complex solution. 



With regard to (3), as but little change in the ionic velocities of one 

 electrolyte in a solution can be produced by the presence of small quanti- 

 ties of others, the value of the conductivity, at infinite dilution, of an elec- 

 trolyte in a complex solution, may be taken to be the same as in a simple 

 solution, provided the complex solution is sutiiciently dilute. Hence, in 

 calculating the conductivity of complex solutions which are dilute, the 

 values of jn orj, // qt,.,, etc., determined by experiments with simple solu- 

 tions, may be employed. The error involved in emploj'ing such values, 

 however, may be expected to increase with the concentration of the 

 solutions. 



With regard to (1) and (2), it is the object of this paper to show how 

 the numbers of gramme-equivalents of the electrolytes present in a solu- 

 tion, and their coefficients of ionisation, may in all cases be determined, 

 ideally at least, by the aid of observations on the conductivity of simple 

 solutions only. 



According to the dissociation theory, any electrolyte in a solution is 

 partially dissociated into its constituent ions, the state of dissociation 

 being one of equilibrium, provided the frequency with which mole- 



