The electrical impedance measured at p‐type and highly doped n‐type Si electrodes in solutions in the potential range of pore formation has been interpreted using a basic model. This model includes two electrochemical reactions (hole capture and electron injection) followed by a chemical oxidation reaction, and accounts for the main results reported in the literature. The electrical impedance has been calculated for the anodic dissolution proceeding both under depletion‐layer and Helmholtz‐layer control. It has been concluded that the impedance and, in particular, the inductive loop measured in the onset region of the anodic dissolution can be explained fairly well on the basis of the model and assuming depletion layer control. The inductive loop is ascribed to electron injection from a surface intermediate of the dissolution process into the conduction band.