On heating NaX with `H_(2)SO_(4)` and `MnO_(2)` the halogens that cannot be prepared is ……..

Options

A. `I_(2)`
B. `CI_(2)`
C. `Br_(2)`
D. `F_(2)`

Answer

To solve the question of which halogen cannot be prepared by heating NaX with H₂SO₄ and MnO₂, we can follow these steps:

### Step 1: Understand the Reactants
We are given sodium halides (NaX), where X can be fluorine (F), chlorine (Cl), bromine (Br), or iodine (I). We are also using sulfuric acid (H₂SO₄) and manganese dioxide (MnO₂) in the reaction.

### Step 2: Identify the Reaction
When sodium halides are heated with H₂SO₄ and MnO₂, the halides can be oxidized to form their respective halogen gases (Cl₂, Br₂, I₂). The general reaction can be represented as:
\[ \text{NaX} + \text{H₂SO₄} + \text{MnO₂} \rightarrow \text{Halogen} + \text{by-products} \]

### Step 3: Analyze Each Halogen
- **Chlorine (Cl₂)**: Chloride ions (from NaCl) can be oxidized by H₂SO₄ and MnO₂ to form Cl₂.
- **Bromine (Br₂)**: Bromide ions (from NaBr) can also be oxidized to form Br₂.
- **Iodine (I₂)**: Iodide ions (from NaI) can be oxidized to form I₂.

### Step 4: Consider Fluorine (F₂)
Fluorine is a very strong oxidizing agent, even stronger than H₂SO₄ and MnO₂. This means that when you try to oxidize fluoride ions (from NaF) to form F₂, the reaction does not proceed as expected because fluorine will oxidize H₂SO₄ and MnO₂ instead.

### Step 5: Conclusion
Based on the analysis, the halogen that cannot be prepared by heating NaX with H₂SO₄ and MnO₂ is **Fluorine (F₂)**.

### Final Answer
The halogen that cannot be prepared is **F₂**.

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