An HCl electrolyzer utilizing a membrane with catalytic electrodes physically bonded to the surfaces of the membrane is provided with an electron current conducting structure which comprises an array of individual current conducting elements contacting the electrode. The cell is operated at high temperatures (60.degree.-90.degree. C.) to take advantage of the reduction of electrode overpotential at these temperatures but with low feed acid concentrations (.ltoreq.9M) to minimize hydrogen chloride in the chlorine, i.e, HCl vapor pressure is below 0.1 atmospheres--76 Torr. There is also a large decrease in membrane resistance as temperature is increased. Simultaneously O.sub.2 evolution is suppressed to maintain O.sub.2 content in the chlorine at 0.1% or less.