The 2 e, 1H + reaction (six-member fence scheme) is studied for a surface reaction (adsorbed species, Langmuir isotherm, or monolayer-modified electrodes) or for a heterogeneous electrochemical reaction with protonations occurring in solution near the electrode. It is assumed that the symmetry factors of the electrochemical reactions are equal to 0.5 and that the protonations are at equilibrium. The influence of the disproportionation reactions is neglected; the conditions in which this can be done are discussed. It is shown that with these hypotheses, the reaction behaves as a bielectronic process, with apparent rate constants which depend on the pH and on the difference between the redox potentials of the individual reactions. The slopes of the variations of the logarithm of the apparent rate constants with pH can be 0, ±0.25, ±0.50 or ±0.75 according to the region of pH, instead of 0 or ±0.50 for the four-member square scheme.