Direct iodination of methane is not practicable because -

Options

A. Iodine–iodine bond is easily broken
B. HI formed in the reaction reduces `CH_(3)I` to `CH_(4)`
C. `CH_(3)I` is unstable
D. `CH_(3)` is formed with difficulty

Answer

**Step-by-Step Solution:**

1. **Understanding Iodination**: Iodination refers to the process of adding iodine (I2) to a molecule. In this case, we are considering the iodination of methane (CH4).

2. **Reaction Overview**: When methane undergoes iodination, the expected reaction is:
\[ \text{CH}_4 + \text{I}_2 \rightarrow \text{CH}_3\text{I} + \text{HI} \]
Here, methyl iodide (CH3I) and hydrogen iodide (HI) are formed.

3. **Reversibility of the Reaction**: The reaction is reversible, meaning that the products can revert back to the reactants. This is due to the formation of HI, which is a strong reducing agent. The HI can react with CH3I to regenerate methane:
\[ \text{CH}_3\text{I} + \text{HI} \rightarrow \text{CH}_4 + \text{I}_2 \]

4. **Impact of HI**: The presence of HI in the reaction means that the iodination of methane does not proceed to completion. Instead, it can revert back to methane, making it impractical to achieve a significant yield of methyl iodide.

5. **Need for Strong Oxidizing Agents**: To overcome the reversibility of the reaction, a strong oxidizing agent like HIO3 can be introduced. This agent would help in oxidizing HI, thus driving the reaction forward and preventing the back reaction:
\[ \text{HIO}_3 + \text{HI} \rightarrow \text{Products} \]
This would help in maintaining the concentration of the products and making the iodination more feasible.

6. **Conclusion**: Therefore, the direct iodination of methane is not practicable due to the reversible nature of the reaction, where the formation of HI leads to the regeneration of methane.

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