On addition of conc. `H_(2)SO_(4)` to a chloride salt, colourless fumes are evolved but in case of iodide salt, violet fumes come out. This is because

Options

A. `H_(2)SO_(4)` reduces HI to `I_(2)`
B. HI is of violet colour
C. HI gets oxidised to `I_(2)`
D. HI changes to `HIO_(3)`

Explanation

To understand why the addition of concentrated H₂SO₄ to chloride salts produces colorless fumes while the same addition to iodide salts produces violet fumes, we can break down the reactions step by step.

### Step 1: Reaction of Concentrated H₂SO₄ with Chloride Salt
1. **Identify the chloride salt**: Let's take sodium chloride (NaCl) as an example.
2. **Write the reaction**: When concentrated H₂SO₄ is added to NaCl, the following reaction occurs:
\[ \text{NaCl} + \text{H}_2\text{SO}_4 \rightarrow \text{Na}_2\text{SO}_4 + \text{HCl} \]
3. **Identify the product**: The product HCl is a colorless gas.
4. **Conclusion**: Therefore, the fumes evolved are colorless due to the formation of HCl.

### Step 2: Reaction of Concentrated H₂SO₄ with Iodide Salt
1. **Identify the iodide salt**: Let's take sodium iodide (NaI) as an example.
2. **Write the reaction**: When concentrated H₂SO₄ is added to NaI, the following reaction occurs:
\[ \text{NaI} + \text{H}_2\text{SO}_4 \rightarrow \text{Na}_2\text{SO}_4 + \text{HI} \]
3. **Identify the product**: The product HI is a reducing agent.
4. **Reduction and Oxidation**: HI can reduce H₂SO₄. The reaction can be represented as:
\[ 2 \text{HI} + \text{H}_2\text{SO}_4 \rightarrow \text{SO}_2 + \text{I}_2 + 2 \text{H}_2\text{O} \]
5. **Identify the product**: The iodine (I₂) produced is a violet-colored gas.
6. **Conclusion**: Therefore, the fumes evolved are violet due to the formation of iodine.

### Final Conclusion
- **Chloride salts** produce **colorless fumes** (HCl) because HCl is a colorless gas.
- **Iodide salts** produce **violet fumes** (I₂) because iodine is a violet-colored gas.