The steady-state distribution of ionic charges in a liquid, in the presence of surface adsorption, is determined. The effect of an electric field applied by means of blocking electrodes is considered. The analysis shows that the surface adsorption of ions dissolved in the liquid is responsible for an asymmetry in the electric-field distribution. In the model, the liquid is assumed to be dielectric but to contain impurities. These impurities, by means of a chemical reaction, can bring about ions. The theory takes into account the activation energy for the ionization chemical reaction and the adsorption energy of the ions at the surface.