Write the anode and cathode reactions occur in the operation of a lead storage battery. Mention the
electrolyte used in the battery.
Answers
Answer:
Net cell reaction: Pb + PbO(s) + 4H+ + 2SO42– → 2PbSO4(s) + 2H2O
Net charging reaction:
2PbSO4(s) + 2H2O (charging) → Pb(s) + PbO2(s) + 4H++ 2SO42–
Explanation:
A lead storage cell may be represented as:
Pb | PbSO4(s) | H2SO4 (40%) | PbO2(s) | Pb
(Anode) (Cathode)
The reactions which take place in the cell during discharge are,
At anode: (oxidation) Pb + SO42–→PbSO4(s) + 2e–
At cathode: (reduction) PbO2(s) + 4H+ + SO42– + 2e– → PbSO4(s) + 2H2O
Net cell reaction: Pb + PbO(s) + 4H+ + 2SO42– → 2PbSO4(s) + 2H2O
The reactions taking place on the two electrodes during recharging are,
Negative electrode: PbSO4(s) + 2e– electric current ( ) dc→ Pb(s) +SO42– (aq) (reduction)
Positive electrode: PbSO4(s) + 2H2O (electric current) → PbO2(s) + 4H+ +SO42–+ 2e–(oxidation)
Net charging reaction:
2PbSO4(s) + 2H2O (charging) → Pb(s) + PbO2(s) + 4H++ 2SO42–