When a lead storage battery is recharged

Options

A. Pb is formed
B. `H_(2)SO_(4)` is formed
C. `H_(2)SO_(4)` is consumed
D. Both (1) & (2)

Answer

To solve the question "When a lead storage battery is recharged," we need to understand the chemical processes that occur during both the discharging and recharging phases of the battery.

### Step-by-Step Solution:

1. **Understand the Discharging Process:**
- During discharging, lead (Pb) and lead dioxide (PbO2) react with sulfuric acid (H2SO4) to produce lead sulfate (PbSO4) and water (H2O).
- The half-reactions are:
- At the anode: Pb → Pb^2+ + 2e^- (oxidation)
- At the cathode: PbO2 + 4H^+ + 2e^- → PbSO4 + 2H2O (reduction)
- The overall reaction during discharging is:
\[ Pb + PbO2 + 2H2SO4 \rightarrow 2PbSO4 + 2H2O \]

2. **Understand the Recharging Process:**
- When the battery is recharged, the reactions reverse. Lead sulfate (PbSO4) reacts with water (H2O) in the presence of an external current to regenerate lead (Pb), lead dioxide (PbO2), and sulfuric acid (H2SO4).
- The half-reactions during recharging are:
- At the anode: PbSO4 + 2e^- → Pb + H2SO4 (oxidation)
- At the cathode: PbSO4 + 2H2O → PbO2 + 4H^+ + 2e^- (reduction)
- The overall reaction during recharging is:
\[ 2PbSO4 + 2H2O \rightarrow Pb + PbO2 + 2H2SO4 \]

3. **Analyzing the Options:**
- From the recharging process, we see that:
- Lead (Pb) is formed.
- Lead dioxide (PbO2) is formed.
- Sulfuric acid (H2SO4) is regenerated (not consumed).
- Therefore, the correct options regarding what happens when a lead storage battery is recharged are:
- Pb is formed (True)
- H2SO4 is formed (True)
- H2SO4 is consumed (False)
- The correct answer is both first and second options are correct.

4. **Final Answer:**
- The answer is option D: Both first and second.