Liquid Junction Potential in Potentiometric Titrations. 5. Deduction of the Potential Functions for E.M.F. Cells with Complex Formation and with Liquid Junctions of the Type AY|AY+ BYz(B) + HY + AyL.

Abstract

Equations were derived, in a general form, for the calculation of the total cell e.m.f. for cells containing liquid junctions of constant ionic medium type, where formation of strong complexes takes place. The total cell e.m.f. is: EJ = E0J + (g/zJ) log cJfJTS2 + ED + EDf Here, (A+, Y-) is the ionic medium, J is the potential-determining ion, Bz(B)+ is the central metal ion, ED is the ideal diffusion potential (Henderson term), EDf is the contribution of the activity coefficients to the diffusion potential, AyL is the ligand. fJTS2 denotes the activity coefficients in the terminal solution TS2. The concentration of a chosen ion of the ionic medium, C, should be in the range 0.5 < or = C < or = 3 mol dm-3. The charge of the metal ion Bz(B)+ should be < or = 3. The total potential anomalies in the cells are delta EJ = (g/zJ) log fJTS2 + ED + EDf