An experimental study of the anodic behaviour of nickel in acidic media is carried out by steady state polarization curves and faradaïc impedance measurements as a function of various parameters related to the electrolyte: pH, concentration and the nature of the anions. We propose several models of the electrode reaction path based on heterogenous chemical kinetic concepts. By a convenient numerical fitting method, we calculate a set of kinetic parameters which are afterwards put into the theoretical equations for dc and the impedance. By this procedure we are able to choose a general model accounting for the behaviour of nickel in a wide range of experimental conditions: active dissolution, passivity, secondary passivity and the oxidation of OH− to molecular oxygen.