During discharge of a lead storage cell the density of sulphuric acid in the cell:

Options

A. increasing
B. decreasing
C. remains uncharged
D. initially increases but decreases subsequently

Explanation

To solve the question regarding the behavior of the density of sulfuric acid during the discharge of a lead storage cell, we can break down the process step by step.

### Step-by-Step Solution:

1. **Understanding the Lead Storage Battery**:
- The lead storage battery, also known as a lead-acid battery, uses dilute sulfuric acid (H2SO4) as its electrolyte.

2. **Reactions During Discharge**:
- During the discharge process, two main reactions occur: oxidation at the anode and reduction at the cathode.
- **Anode Reaction**: Lead (Pb) is oxidized to lead ions (Pb²⁺).
\[ \text{Pb} \rightarrow \text{Pb}^{2+} + 2e^- \]
- The lead ions react with sulfate ions (SO₄²⁻) from the sulfuric acid to form lead sulfate (PbSO₄).
\[ \text{Pb}^{2+} + \text{SO}_4^{2-} \rightarrow \text{PbSO}_4 \]

3. **Cathode Reaction**:
- At the cathode, lead dioxide (PbO₂) is reduced to lead ions (Pb²⁺).
\[ \text{PbO}_2 + 2\text{H}^+ + 2e^- \rightarrow \text{Pb}^{2+} + 2\text{H}_2\text{O} \]
- The lead ions again react with sulfate ions to form lead sulfate (PbSO₄).

4. **Formation of Water**:
- As the reactions proceed, water is formed due to the reduction of PbO₂. This reaction leads to an increase in the volume of water in the electrolyte.

5. **Effect on Density**:
- The initial density of the sulfuric acid solution is around 1.30 g/cm³. As the discharge progresses, water is produced, diluting the sulfuric acid solution.
- Consequently, the density of the sulfuric acid decreases as the concentration of sulfuric acid decreases due to the formation of water and the consumption of sulfate ions.

6. **Conclusion**:
- Therefore, during the discharge of a lead storage cell, the density of sulfuric acid **decreases**.

### Final Answer:
The density of sulfuric acid in the lead storage cell during discharge **decreases**.

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