A primary voltaic cell consisting of a zinc anode and a cathode of mercury(II) oxide (HgO) mixed with graphite. The electrolyte is potassium hydroxide (KOH) saturated with zinc oxide, the overall reaction being:
Zn + HgO → ZnO + Hg
The e.m.f. is 1.35 volts and the cell will deliver about 0.3 ampere-hour per cm3.
Subjects: Chemistry — Physics.