The`-OH` group of Methyl alcohol cannot be replaced by chlorine by the the action of

Options

A. Chlorine
B. Hydrogen cloride
C. Phosphorus trichloride
D. Phosphorus pentachloride

Answer

To solve the question regarding the inability of the -OH group of methyl alcohol (CH₃OH) to be replaced by chlorine through various reactions, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding Methyl Alcohol**:
- Methyl alcohol, also known as methanol, has the formula CH₃OH. The -OH group is a hydroxyl group that characterizes alcohols.

2. **Reaction with Chlorine (Cl₂)**:
- When methyl alcohol reacts with chlorine, no substitution reaction occurs. Chlorine typically reacts with alkenes or alkanes under certain conditions, but it does not replace the -OH group in alcohols directly. Therefore, this reaction does not lead to the formation of any product.

3. **Reaction with Hydrogen Chloride (HCl)**:
- Methyl alcohol reacts with hydrogen chloride to form methyl chloride (CH₃Cl) and water (H₂O). This reaction proceeds via an SN2 mechanism, where the -OH group is protonated to form a better leaving group (H₂O), allowing the chloride ion (Cl⁻) to attack the carbon atom.

4. **Reaction with Phosphorus Trichloride (PCl₃)**:
- Methyl alcohol reacts with phosphorus trichloride to produce methyl chloride (CH₃Cl) and phosphorous acid (H₃PO₃). In this reaction, the -OH group is replaced by a chlorine atom, indicating that this reaction does lead to substitution.

5. **Reaction with Phosphorus Pentachloride (PCl₅)**:
- Methyl alcohol reacts with phosphorus pentachloride to yield methyl chloride (CH₃Cl), phosphorous oxychloride (POCl₃), and hydrochloric acid (HCl). Similar to PCl₃, this reaction also results in the substitution of the -OH group.

6. **Conclusion**:
- Among the options provided, the only reagent that does not replace the -OH group of methyl alcohol with chlorine is chlorine (Cl₂). Therefore, the answer to the question is **chlorine**.

### Final Answer:
The -OH group of methyl alcohol cannot be replaced by chlorine by the action of **chlorine (Cl₂)**.