The Leclanchè battery

In the Leclanché dry cell the solutions in which electrodes are immersed are replaced by gelatinous mixtures. The outer casing is in zinc and works as an anode. A graphite, bar immersed in the mixture has the sole function of conductor for the same, consisting of manganese oxide, ammonium chloride, zinc chloride, carbon black, starch and water, which acts as a cathode. During operation, the zinc is oxidised while the manganese dioxide is reduced. The e.f.m. expressed by the Leclanché battery is, therefore, approximately 1.5 volts. The Leclanché battery loses charge when the reactions reach equilibrium.