The reactivities of `CH_(3)Cl, CH_(3)CH_(2)CH_(2)Cl and C_(6)H_(5)Cl` are in the order

Options

A. `CH_(3)Cl gt CH_(3)CH_(2)CH_(2)Cl gt C_(6)H_(5)Cl`
B. `CH_(3)CH_(2)CH_(2)Cl gt CH_(3)Cl gt C_(6)H_(5)Cl`
C. `C_(6)H_(5)Cl gt CH_(3)CH_(2)CH_(2)Cl gt CH_(3)Cl`
D. `CH_(3)Cl gt C_(6)H_(5)Cl gt CH_(3)CH_(2)CH_(2)Cl`

Explanation

To determine the reactivities of the compounds \( CH_3Cl \), \( CH_3CH_2CH_2Cl \), and \( C_6H_5Cl \), we need to analyze the steric hindrance and the type of reaction mechanism involved.

### Step-by-Step Solution:

1. **Identify the Compounds**:
- The compounds given are:
- \( CH_3Cl \) (Methyl chloride)
- \( CH_3CH_2CH_2Cl \) (Propyl chloride)
- \( C_6H_5Cl \) (Benzyl chloride)

2. **Understand the Reaction Mechanism**:
- The reactivity of alkyl halides in nucleophilic substitution reactions can be influenced by steric hindrance.
- The two common mechanisms are \( S_N1 \) and \( S_N2 \):
- \( S_N2 \) reactions involve a backside attack by the nucleophile, which is hindered by bulky groups around the carbon atom.
- \( S_N1 \) reactions involve the formation of a carbocation intermediate, which is also affected by steric hindrance.

3. **Analyze Steric Hindrance**:
- **\( CH_3Cl \)**: This compound has no steric hindrance as it has only hydrogen atoms attached to the carbon. It is highly reactive in \( S_N2 \) reactions.
- **\( CH_3CH_2CH_2Cl \)**: This compound has a straight-chain structure with a little more steric hindrance compared to \( CH_3Cl \) but is still relatively reactive.
- **\( C_6H_5Cl \)**: The benzyl chloride has a bulky benzene ring, which creates significant steric hindrance. This makes it less reactive in \( S_N2 \) reactions compared to the other two.

4. **Order of Reactivity**:
- Based on the analysis of steric hindrance:
- \( CH_3Cl \) (least steric hindrance) > \( CH_3CH_2CH_2Cl \) (moderate steric hindrance) > \( C_6H_5Cl \) (most steric hindrance).
- Therefore, the order of reactivity is:
\[ CH_3Cl > CH_3CH_2CH_2Cl > C_6H_5Cl \]

5. **Conclusion**:
- The reactivities of the compounds are in the order:
\[ CH_3Cl > CH_3CH_2CH_2Cl > C_6H_5Cl \]