Which of the following compounds can be used for the detection `H_2SO_4` gas

Options

A. Conc `H_2SO_4`
B. `P_2O_5`
C. Fused `CaCl_2`
D. Anhydrous `AI_2O_3`

Answer

To determine which compounds can be used for the detection of sulfuric acid (H₂SO₄) gas, we can analyze the options provided in the question. Here’s a step-by-step solution:

### Step 1: Identify the Compounds
The compounds mentioned for the detection of sulfuric acid gas are:
1. P₂O₅ (Phosphorus pentoxide)
2. Calcium chloride (CaCl₂)
3. N₂O₃ (Dinitrogen trioxide)

### Step 2: Understand the Detection Mechanism
Sulfuric acid gas can be detected through its reaction with certain compounds. The compounds that can absorb or react with sulfuric acid will indicate its presence.

### Step 3: Analyze Each Compound
1. **P₂O₅**: Phosphorus pentoxide is a strong dehydrating agent and can react with water to form phosphoric acid. It can also react with sulfuric acid, making it a suitable compound for detection.

2. **Calcium Chloride (CaCl₂)**: Calcium chloride is hygroscopic and can absorb moisture. When it absorbs sulfuric acid, it can form calcium sulfate (CaSO₄), indicating the presence of H₂SO₄ gas.

3. **N₂O₃**: Dinitrogen trioxide does not have a significant reaction with sulfuric acid gas and is not typically used for its detection.

### Step 4: Conclusion
Based on the analysis:
- **P₂O₅** and **Calcium Chloride (CaCl₂)** can be used for the detection of sulfuric acid gas.
- **N₂O₃** is not suitable for this purpose.

### Final Answer
The compounds that can be used for the detection of H₂SO₄ gas are:
- P₂O₅
- Calcium chloride (CaCl₂)

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