We report here a general model for the description of the redox potential behaviour of certain electrodes in complex mixtures based on the study of redox process. The model has been developed theoretically and has also been experimentally verified. The model allows to state broad-spectrum equations which describe the behaviour of the potential of second and third order Faradic electrodes. Experimental verification of the model was carried out using common redox electrodes. The model was used to predict the redox behaviours in the following cases; (i) study of the potential variation of a Silver electrode as function of the pH, (ii) the redox potential of an Ag/AgCl electrode as function of the chloride concentration at different pH values, (iii) the potential of a Ag/AgBr electrode in the presence of certain amounts of chloride and (iv) the quantitative solid-solid transformation between AgBr and AgCl phases. There was found a remarkably good agreement between the experimental and theoretical values. (c) 2006 Elsevier B.V. All rights reserved.