Lead Dioxide and Sulfuric Acid (Lead-Acid Battery Discharge)
PbO2 + Pb + 2H2SO4 → 2PbSO4 + 2H2O
Overview
During discharge, lead dioxide (cathode, Pb⁴⁺) is reduced to lead sulfate while lead metal (anode, Pb⁰) is oxidized to lead sulfate. Both electrodes convert to PbSO₄, and the sulfuric acid electrolyte is consumed. The cell potential is 2.05 V. Charging reverses the reaction.
Participants
| Role | Substance | Coefficient | State |
|---|---|---|---|
| Reactant | Lead Pb | 1 | (s) |
| Reactant | Sulfuric Acid H₂SO₄ | 2 | (aq) |
| Product | Water H₂O | 2 | (l) |
Everyday Example
Every car battery is a lead-acid battery using this reversible redox reaction. Starting your car draws hundreds of amps from this reaction.
Industrial Importance
Lead-acid batteries represent a $40+ billion global industry used in vehicles, UPS systems, and energy storage. Over 99% of lead-acid batteries are recycled.
Properties
- Type
- Redox
- Reversible
- Yes
- Energy
- Exothermic
- ΔH
- -359.4 kJ/mol
Related Reactions
Aqua Regia Dissolving Gold
Bleaching with Sodium Hypochlorite
Cerium(IV) Reduction by Iron(II)
Chlorine Oxidation of Bromide
Chromate-Dichromate Equilibrium
Contact Process SO₂ Oxidation
Copper Displaced by Iron
Copper Oxidation by Nitric Acid
Copper Patina Formation (Verdigris)
Copper Reduction of Silver Ion
Frequently Asked Questions
What is the equation for Lead Dioxide and Sulfuric Acid (Lead-Acid Battery Discharge)?
The balanced equation is: PbO₂ + Pb + 2H₂SO₄ → 2PbSO₄ + 2H₂O.
What type of reaction is Lead Dioxide and Sulfuric Acid (Lead-Acid Battery Discharge)?
Lead Dioxide and Sulfuric Acid (Lead-Acid Battery Discharge) is a redox reaction. It is reversible under certain conditions.
Is Lead Dioxide and Sulfuric Acid (Lead-Acid Battery Discharge) exothermic or endothermic?
Lead Dioxide and Sulfuric Acid (Lead-Acid Battery Discharge) is exothermic (releases energy). The enthalpy change (ΔH) is -359.4 kJ/mol.