Dry cell
A dry cell is a compact primary electrochemical cell that supplies electrical energy at small currents. Like all electrochemical cells, it gets its electrical energy from an internal chemical reaction. The cell is wrapped in a sheet of zinc, inside which is a carbon rod. The space between the zinc and the carbon is packed with a mixture of moist chemicals. The cell has two contacts: the positive (+) terminal (or cathode) and the negative (-) terminal (or anode). The anode (-), which is the zinc casing oxidises according to the following half-equation: Zn(s) → Zn2+(aq) + 2e- The graphite rod, emersed in the electrolyte paste (containing manganese dioxide, Mn2O3) is the cathode (+) and reduces according to the following half-equation: 2MnO2(s) + 2H+(aq) + 2e- → Mn2O3(s) + H2O(l)
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