Write the chemistry of recharging the lead storage battery, highlighting all the materials that are involved during recharging.
During recharging of a lead storage battery, the reactions that occurred during discharge are reversed by passing current in the opposite direction. The key materials involved during recharging are lead sulphate (PbSO₄), lead (Pb), lead dioxide (PbO₂), sulphuric acid (H₂SO₄), and water (H₂O).
During recharging, PbSO₄ at the anode is converted back to Pb, and PbSO₄ at the cathode is converted back to PbO₂. The overall reaction during recharging is the reverse of the discharge reaction:
2PbSO₄(s) + 2H₂O(l) → Pb(s) + PbO₂(s) + 2H₂SO₄(aq)
This process restores the original electrode materials and the concentration of sulphuric acid electrolyte, making the battery ready for reuse.
Explanation
The textbook explains that a lead storage battery consists of a lead anode, a lead dioxide (PbO₂) cathode, and 38% sulphuric acid as electrolyte. During discharge, both electrodes get converted to PbSO₄. During recharging, this process is reversed - PbSO₄ at anode converts to Pb, and PbSO₄ at cathode converts to PbO₂. The overall cell reaction is reversed during charging.
Solution Steps
Step 1: Identify the materials in the lead storage battery - lead anode, PbO₂ cathode, H₂SO₄ electrolyte
Step 2: Understand that during discharge, both electrodes form PbSO₄
Step 3: During recharging, reverse the reactions - PbSO₄ converts back to Pb at anode and PbO₂ at cathode
Step 4: Write the overall reversed reaction showing all materials involved