Corrosion or its inhibition is examined in terms of competitive reactions at the metal/solution interface. These surface reactions involve hydroxyl-assisted metal dissolution and adsorption of an inhibitive ion or molecule, with the system being described by a pair of autonomous nonlinear differential equations. Both Langmuir and Temkin adsorption isotherms are considered. For Temkin adsorption there may exist as many as four critical points. The behavior of the system near the critical points has been studied using eigenvalue analysis and the phase:plane method. As the system drifts in time toward any given stable critical point, there is a corresponding anodic current flow. For some stable critical points, the current vanishes and inhibition occurs, while for others ii does not and corrosion occurs.