Sulphuric acid is considered as the king of chemicals. The prosperity of any country is measured by the amount of sulphuric acid it consumes. Sulphuric acid is, thus, a substance of very great commercial importance as it used practically ine every important industry. This is due to the following properties of sulphuric acid :
(a) acidic nature
(b) oxidising nature
(c) dehydrating nature
(d) sulphonation.
Which of the following reactions depict the oxidising behaviour of `H_2 SO_4` ?

Options

A. `2HI + H_2 SO_4 rarr I_2 + SO_2 + 2H_2 O`
B. `NaCl + H_2 SO_4 rarr NaHSO_4 + HCl`
C. `2 NaOH + H_2 SO_4 rarr Na_2 SO_4 + 2H_2 O`
D. `2 PCl_5 + H_2 SO_4 rarr 2POCl_3 + 2 HCl + SO_2 Cl_2`

Explanation

To determine which reaction depicts the oxidizing behavior of sulfuric acid (H₂SO₄), we need to analyze the oxidation states of the elements involved in the reactions. The oxidizing behavior is characterized by the ability of a substance to gain electrons or increase the oxidation state of another substance.

### Step-by-Step Solution:

1. **Identify the Reactions**:
We need to examine the provided reactions involving sulfuric acid to see which one shows a change in oxidation states indicating oxidation.

2. **Analyze the First Reaction**:
The reaction is:
\[ 2 HI + H_2SO_4 \rightarrow I_2 + SO_2 + 2 H_2O \]
- Assign oxidation states:
- In HI: H = +1, I = -1
- In H₂SO₄: H = +1, S = +6, O = -2
- In I₂: I = 0
- In SO₂: S = +4

- Changes in oxidation states:
- Iodine changes from -1 (in HI) to 0 (in I₂), indicating oxidation.
- Sulfur changes from +6 (in H₂SO₄) to +4 (in SO₂), indicating reduction.

3. **Conclusion for First Reaction**:
Since iodine is oxidized and sulfuric acid is reduced, this reaction demonstrates the oxidizing behavior of H₂SO₄. Thus, this reaction is a valid example of oxidation.

4. **Analyze Other Reactions**:
For the other reactions, we need to check if there are any changes in the oxidation states of sulfur or other elements:
- If the oxidation state of sulfur remains +6 in the other reactions, then H₂SO₄ is not acting as an oxidizing agent in those cases.

5. **Final Answer**:
The reaction that depicts the oxidizing behavior of sulfuric acid is:
\[ 2 HI + H_2SO_4 \rightarrow I_2 + SO_2 + 2 H_2O \]
Therefore, the answer is **Option A**.