Final answer:
During the discharge phase of a lead storage battery, the anode and cathode undergo redox reactions resulting in the build-up of lead (II) sulfate and changes in the density of the electrolyte.
Step-by-step explanation:
Cell Reactions in Lead Storage Battery During Discharge
During the discharge of a lead storage battery, certain chemical reactions occur at the anode and cathode. At the anode, spongy lead is oxidized to lead (II) sulfate:
- Pb(s) + SO42- (aq) → PbSO4(s) + 2e-
Meanwhile, at the cathode, lead dioxide is reduced to lead (II) sulfate:
- PbO2(s) + 4H+ (aq) + SO42- (aq) + 2e- → PbSO4(s) + 2H2O(l)
The overall reaction during discharge can be represented as:
- Pb(s) + PbO2(s) + 2H2SO4(aq) → 2PbSO4(s) + 2H2O(l)
These reactions lead to the build-up of lead (II) sulfate on the electrodes, a decrease in the concentration of sulfuric acid, and an increase in the production of water, altering the density of the electrolyte.