The lead-acid battery, also called a lead storage battery, is the battery of choice for starting automobiles. It contains 6 cells connected in series, each composed of a lead oxide cathode "sandwiched" between 2 lead anodes. Insulating separators are placed between the electrodes to prevent internal short-circuits.
Aqueous sulfuric acid is the electrolyte.
When the battery is being discharged, the following reaction takes place:
Reaction 1
The electrode reactions, both written as reductions, are shown in Table 1.
Table 1
Half-reaction
E?V)
PbO2(s) + SO42-(aq) + 4H+(aq) + 2e-
PbSO4(s) + 2H2O
PbSO4(s) + 2e- Pb(s) + SO42-(aq)
1.69
?.36
As a car operates, the battery is recharged by electricity produced by the car's alternator, an AC generator whose ultimate power source is the car's internal combustion engine. In spite of this, batteries eventually lose their power. The battery is said to be "dead" when Reaction 1 has proceeded completely to the right.
Which of the following occurs as the battery is being recharged?
