Assertion: As a lead storage battery gets discharged, density of the electrolyte present in it decreases.
Reason: lead and lead dioxide both react with sulphuric acid to form lead sulphate.

Options

A. If both assertion and reason are true, and reason is the true explanation of the assertion
B. if both assertion and reason are true, but reason is not the true explanation of the assertion.
C. if assertion is true, but reason is false.
D. If both assertion and reason are false.

Explanation

To analyze the given assertion and reason regarding a lead storage battery, we can break down the solution into steps:

### Step 1: Understand the Assertion
The assertion states that "as a lead storage battery gets discharged, the density of the electrolyte present in it decreases."

### Step 2: Analyze the Discharge Process
During the discharge process of a lead storage battery, lead (Pb) and lead dioxide (PbO2) react with sulfuric acid (H2SO4) in the electrolyte. The reactions can be summarized as follows:

1. **Reaction with Lead (Pb)**:
\[ \text{Pb} + \text{H}_2\text{SO}_4 \rightarrow \text{PbSO}_4 + 2\text{e}^- \]

2. **Reaction with Lead Dioxide (PbO2)**:
\[ \text{PbO}_2 + 2\text{H}_2\text{SO}_4 + 2\text{e}^- \rightarrow \text{PbSO}_4 + 2\text{H}_2\text{O} \]

### Step 3: Effect on Electrolyte Density
As the battery discharges, the sulfate ions (SO4^2-) from sulfuric acid are consumed to form solid lead sulfate (PbSO4). This reaction decreases the concentration of sulfuric acid in the electrolyte, leading to a decrease in the density of the electrolyte.

### Step 4: Understand the Reason
The reason provided states that "lead and lead dioxide both react with sulfuric acid to form lead sulfate." This statement is correct and supports the assertion. As lead and lead dioxide react with sulfuric acid, they form lead sulfate, which decreases the concentration of sulfuric acid in the electrolyte.

### Conclusion
Both the assertion and the reason are correct, and the reason correctly explains the assertion.

### Final Answer:
- **Assertion**: True
- **Reason**: True
- **Explanation**: The density of the electrolyte decreases as the concentration of sulfuric acid decreases due to its reaction with lead and lead dioxide to form lead sulfate.

---