Which of the following reaction represents the oxidising behaviour of `H_(2)SO_(4)` :-

Options

A. `2PCl_(5)+H_(2)SO_(4)rarr2POCl_(3)+2HCl+SO_(2)Cl_(2)`
B. `2NaOH+H_(2)SO_(4)rarrNa_(2)SO_(4)+2H_(2)O`
C. `NaCl+H_(2)SO_(4)rarrNaHSO_(4)+HCl`
D. `2HI+H_(2)SO_(4)rarrI_(2)+SO_(2)+2H_(2)O`

Answer

To determine which reaction represents the oxidizing behavior of \( H_2SO_4 \), we need to analyze the oxidation states of the elements involved in each reaction. An oxidizing agent is a substance that gets reduced while causing another substance to be oxidized. Here’s a step-by-step solution:

### Step 1: Identify the reactions
We need to examine each of the provided reactions to see if \( H_2SO_4 \) acts as an oxidizing agent.

### Step 2: Analyze the first reaction
- **Reaction**: Phosphorus with \( H_2SO_4 \)
- **Oxidation States**:
- Phosphorus (P) is +5 in both reactants and products.
- Sulfur (S) is +6 in both reactants and products.
- **Conclusion**: No change in oxidation states. This is **not a redox reaction**.

### Step 3: Analyze the second reaction
- **Reaction**: Acid-base reaction (e.g., \( H_2SO_4 \) with a base)
- **Oxidation States**:
- The products are salt and water.
- **Conclusion**: No change in oxidation states. This is **not a redox reaction**.

### Step 4: Analyze the third reaction
- **Reaction**: \( NaCl + H_2SO_4 \)
- **Oxidation States**:
- Chlorine (Cl) is -1 in both reactants and products.
- Sulfur (S) remains +6.
- **Conclusion**: No change in oxidation states. This is **not a redox reaction**.

### Step 5: Analyze the fourth reaction
- **Reaction**: \( I^- + H_2SO_4 \)
- **Oxidation States**:
- Iodine (I) in \( I^- \) is -1 and in elemental form \( I_2 \) is 0.
- Sulfur (S) in \( H_2SO_4 \) is +6 and in \( SO_2 \) is +4.
- **Conclusion**:
- Iodine is oxidized from -1 to 0 (increase in oxidation state).
- Sulfur is reduced from +6 to +4 (decrease in oxidation state).

Since \( H_2SO_4 \) is reduced and \( I^- \) is oxidized, this indicates that \( H_2SO_4 \) is acting as an oxidizing agent.

### Final Answer
The reaction that represents the oxidizing behavior of \( H_2SO_4 \) is the fourth reaction involving iodine (\( I^- \)).

**Correct Option**: D

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