Which one of the following reacts with concentrated sulphuric acid

Options

A. Au
B. Ag
C. Pt
D. Pb

Explanation

To determine which of the given substances reacts with concentrated sulfuric acid (H2SO4), we will analyze each option.

### Step-by-Step Solution:

1. **Identify the Compounds**: The options given are Ag2SO4 (Silver sulfate), SO2 (Sulfur dioxide), and possibly other compounds which are not mentioned in the transcript.

2. **Understand the Reactivity with Concentrated Sulfuric Acid**:
- Concentrated sulfuric acid is a strong acid and dehydrating agent. It can react with various compounds, particularly metal oxides, sulfates, and some non-metals.

3. **Analyze Ag2SO4 (Silver Sulfate)**:
- Silver sulfate can react with concentrated sulfuric acid. The reaction can be represented as:
\[ \text{Ag}_2\text{SO}_4 + \text{H}_2\text{SO}_4 \rightarrow \text{Ag} + \text{SO}_2 + \text{H}_2\text{O} \]
- This indicates that silver sulfate decomposes in the presence of concentrated sulfuric acid.

4. **Analyze SO2 (Sulfur Dioxide)**:
- Sulfur dioxide does not react with concentrated sulfuric acid under normal conditions. It is already a product of the oxidation of sulfur and does not further react with the acid.

5. **Conclusion**:
- Based on the analysis, the compound that reacts with concentrated sulfuric acid is **Ag2SO4**.

### Final Answer:
The correct answer is **Ag2SO4**.

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