Physics · Electrostatics
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Which statement is correct while recharging the automobile battery?
- A
Pb is converted to PbO2
- B
PbSO4 is converted to Ph
- C
Pb is converted to PbSO4
- D
None of the above
Pb oxidized to PBSO4
When the battery is discharging, it acts as a galvanic cell and the following chemical reaction occurs:
Negative:
Pb(s) + HSO4- + H2O (l) → 2e- + PbSO4(s) + H3O+(aq)
Pb is oxidized.
Positive:
PbO2 (s) + HSO4- (aq) + 3H3O+(aq) +2e- → PBSO4 (s) + 5H2O (l)
a) Pb is converted to PbO2:
When recharging an automobile battery, the lead-acid battery undergoes a chemical reaction in which lead dioxide (PbO2) is formed on the positive electrode (anode). During the discharge process, lead dioxide (PbO2) is reduced to lead sulfate (PbSO4) and lead (Pb) on the negative electrode (cathode). During the recharge process, the reverse reaction occurs, and lead (Pb) is oxidized back to lead dioxide (PbO2) on the positive electrode.
b) PbSO4 is converted to Pb:
This statement is incorrect. During the recharging process, lead sulfate (PbSO4) on the negative electrode is reduced to lead (Pb) and lead dioxide (PbO2) during the charging process. It does not directly convert to lead (Pb).
Pb oxidized to PBSO4
When the battery is discharging, it acts as a galvanic cell and the following chemical reaction occurs:
Negative:
Pb(s) + HSO4- + H2O (l) → 2e- + PbSO4(s) + H3O+(aq)
Pb is oxidized.
Positive:
PbO2 (s) + HSO4- (aq) + 3H3O+(aq) +2e- → PBSO4 (s) + 5H2O (l)
this option is incorrect.
Tagged under Physics · Electrostatics · 2013