Write the chemistry of recharging the lead storage battery

Asked by vinodjoshi112233 | 9th Jun, 2017, 03:46: PM

Expert Answer:

In lead storage battery, when H2SO4 is used up during the discharge, the density of H2SO4 falls. When it falls below 1.20  cm-3, the battery needs recharging.
Duriing recharging, the cell is operated like an electrolytic cell, i.e., now electrical energy is suppiled to it from a external source. The electrode are the reverse of those that occur during discharge:
At cathode: PbSO4(s) + 2e- → Pb(s) + SO42-(aq)                                (Reduction)
At anode: PbSO4(s) + 2H2O → PbO2(s) + SO42-(aq) + 4H+(aq) + 2e-      (Oxidation)
Overall reaction: 2PbSO4(s) + 2H2O → Pb(s) + PbO2(s) + 4H+(aq) + 2SO42-(aq) 

Answered by Prachi Sawant | 9th Jun, 2017, 05:06: PM