Iron corrosion in acidic media is a natural phenomenon that converts elemental iron to a more chemically-stable form, i.e. its oxide and hydroxide. In this study, the iron corrosion process is modeled as a completely implicit problem, solved by a novel finite difference model to provide insight into the ionic aspects of corrosion behavior. This new mathematical model eliminates the chemical potential parameters from the corrosion process equations, thereby reducing the need for experimental determination of chemical potentials. The eliminated-chemical-potential-parameters model predicts and quantifies key parameters (concentrations of conjugate base ion, iron (II) ion, hydrogen ion, anodic and cathodic potentials, and the electrical current density) associated with the iron corrosion process in acidic solutions. The rigorous derivation and novel application of the eliminated-chemical-potential-parameters model and its results provide new insights into the iron corrosion process. The present model is also applicable in any industrial process which is associated with metal corrosion. The model helps to guide the design of future corrosion resistant systems, and various experimental studies pertaining to corrosion inhibition techniques. (C) 2019 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.