Activity and osmotic coefficients from the Emf of liquid-membrane cells. VII: Co(ClO4)(2), Ni(ClO4)(2), K2SO4, CdSO4, CoSO4, and NiSO4

The activity coefficients of CdSO4CoSO4, and NiSO4 are determined from the emf of liquid-membrane cells, like those described in the papers I-VI of th is series. The activity coefficients of the auxiliary salts Co(ClO4)(2), Ni (ClO4)(2), and K2SO4, needed to eliminate the problem of extrapolation to i nfinite dilution of the 2-2 salts, are also measured. CdSO4CoSO4 and NiSO4 in the dilute region deviate downward from the limiting law by a larger ext ent than believed in the past, thus creating the need for the activity coef ficients to be recalculated and systematically lowered by 8-16%. The activi ty coefficients of Co(ClO4)(2) and Ni(ClO4)(2), too, need to be corrected b y around -3%. For K2SO4, the original values, although scattered, were subs tantially correct. Fitter's theory best-fit parameter, able to provide the activity and osmotic coefficients of the salts considered, are reported.