Ion and solvent transfers at homoionic junctions between concentrated electrolyte solutions

A unified treatment of liq. junction potentials and membrane potentials which accounts for both ionic and solvent transfers at homoionic junctions between ultra concd. electrolyte solns., also in terms of the primary hydration parameters and the Stokes-Robinson hydration theory, is described. Application to the detn. of cation transference nos., τ+, water transference nos., τw, and primary hydration nos., h, is described as a rational scheme for characterization of concd. electrolytes as possible new salt bridges for the minimization of liq. junction potentials in electroanal. Examples of application of this scheme are presented based on multiple regression anal. of emf. measurements of such homoionicconcn. cells as Ir|Cl2|HCl (m2)‖HCl (m1)|Cl2|Ir and Hg|Hg2SO4|Li2SO4 (m2)‖Li2SO4|Hg, with fixed m1 molality and varied m2 molality. Based on the emf. of analogous homoionic transference cells but with interposed membranes, application of the present procedure can be extended to the detn. of ion and solvent transport parameters, notably the degree of permselectivity, of membranes of use either as selective sensors in electroanal. or selective sepns. in industrial electrochem.