When a lead-acid cell is recharged, the H2 ions move to cathode and SO4 ions go to anode. The following changes then take place.

• A. At Cathode: PbSO4 + H2 → Pb + H2SO4At Anode: PhSO4 + 2H2O → PbO2 + 2H2SO4
• B. At Cathode: PbSO4­ + H2 → Pb + H2SO4At Anode: PhSO4 + H2O → PbO2­ + H2SO4
• C. At Cathode: PhSO4 + H2O → PbO2 + H2SO4At Anode: PbSO4 + H2 → Pb + H2SO4
• D. At cathode: PhSO4­ + 2H2O → PbO2 + 2H2SO4At Anode: PbSO4 + H2 → Pb + H2SO4