From the bases of statistical mechanics a conductance equation is obtained which includes the Bjerrum association concept without making use of any ad hoc chemical model. The Hamiltonian model used is general enough to permit the a posteriori introduction of more specific Gurney cosphere ionic interactions. The former analytical results of Fuoss-Onsager and Falkenhagen et al. become a limit case formulation of the restricted primitive model applied to ions of lower electronic charges in solvents in higher dielectric constants.