Optical isomerism is exhibited by

Options

A. Primary butyl chloride
B. Secondary butyl chloride
C. Tertiary butyl chloride
D. Isobutyl chloride

Explanation

To determine which compound exhibits optical isomerism, we need to identify the presence of a chiral center (or stereocenter) in each compound. A chiral center is a carbon atom that is bonded to four different groups. Let's analyze each option step by step:

### Step 1: Analyze Primary Butyl Chloride
- **Structure**: CH3-CH2-CH2-CH2Cl
- **Chiral Center**: No chiral center is present because the carbon atoms are bonded to identical hydrogen atoms and do not have four different substituents.
- **Conclusion**: Does not exhibit optical isomerism.

### Step 2: Analyze Secondary Butyl Chloride
- **Structure**: CH3-CHCl-CH2-CH3
- **Chiral Center**: The carbon atom bonded to chlorine (C-2) has four different substituents: a chlorine atom, a methyl group (CH3), an ethyl group (CH2CH3), and a hydrogen atom (H).
- **Conclusion**: Exhibits optical isomerism due to the presence of a chiral center.

### Step 3: Analyze Tertiary Butyl Chloride
- **Structure**: (CH3)3C-Cl
- **Chiral Center**: No chiral center is present because the central carbon is bonded to three identical methyl groups and one chlorine atom.
- **Conclusion**: Does not exhibit optical isomerism.

### Step 4: Analyze Isobutyl Chloride
- **Structure**: CH3-CH(CH3)-CH2Cl
- **Chiral Center**: The carbon atom bonded to chlorine (C-2) has three different substituents: a chlorine atom, a methyl group (CH3), and an ethyl group (CH2).
- **Conclusion**: Does not exhibit optical isomerism because it does not have four different substituents.

### Final Conclusion
- The only compound that exhibits optical isomerism is **Secondary Butyl Chloride** (Option B).