Computation of the Dissociation Constant of a 1 : l Electrolyte from Conductance Data Using a Simplified Procedure Conductance studies serve a3 an important tool for the investigation of ionic equilibria. In order t o ohtain quantitative estimatm of the dissociation constant of s. 1:1 electrolyte a. variety of treatments of conductance data is availahle.l-" This note relates t o the simplified procedure which we sdopted in analyzing the data on conductance of solutions of ferrieinium picrate in pyridine (D = 12.3) far determining the dissociation constant of the salt.4 Although the treatment is admittedly a non-sophislicated approach based on simplifying assumptions, the derived dissociation constants are considered accurate enough for most quantitative work. The accuracy of the Ao values is perhaps no better i,han 2 ~ 0 . 2 %or so. I t should be stressed that the present t,reatment does include the activity correction and is considered adequate in that respect provided the data relate to low ionic strength. Fortunat,ely, the latter condition is rather easy to obtain, while using low dielectric solvents, at low concentrstions of electrolytes of dissociation constants of -4 X 10-a or less, a$ considered in Fooss-Kraus treatment.2 I t should he remarked further that although the significance of the physical constants, viz., Aa, K, and an derived from the more comprehensive analyses"ar outweighs the tedium associated with the datsiprocessing, it is considered futile to apply these treatments t o data that are no better than 4 ~ 0 . 1 %in accuracy and also t o cases where dissociation constants good only to *lo-15% would be snfficient. The computer program suitable for dsta-processing according t o our treatment is available on request.
' KRAUS,C. A,, AND BRAY,W. C., J . A m w . Chem. Soc., 35, 1315 (1913).
Fuoss, R. M., AND KRACS,C. A,, J. Amer. Chem. Soc., 55,476 (1933); Fnoss, R. M., J . Amer. C h m . Soc., 57,488 (1935). Fuoss, R. M., AND ACC~SCINA, F . , ' i E l e ~ t r ~ l y tConductance," ic Interscience Publishers, New York, 1959, pp. 195, 226. MUI
