Which of the following molecules is expected to rotate the plane polarized light?

Options

A.
B.
C.
D.

Explanation

To determine which of the given molecules is expected to rotate plane-polarized light, we need to identify if the molecules are optically active. A compound is considered optically active if it meets two main criteria:

1. It must contain at least one chiral carbon atom (a carbon atom bonded to four different substituents).
2. It must not have a plane of symmetry.

Let's analyze each option step by step:

### Step 1: Analyze the first molecule
- Check for chiral carbon: Look for carbon atoms that are bonded to four different groups.
- Check for plane of symmetry: Determine if the molecule can be divided into two symmetrical halves.

**Conclusion for first molecule**:
- It does not have a chiral carbon because all substituents are identical (e.g., CS2 groups).
- Therefore, it cannot rotate plane-polarized light.

### Step 2: Analyze the second molecule
- Identify the carbon atoms and their substituents.
- Check if there is a carbon atom bonded to four different groups.

**Conclusion for second molecule**:
- There is a chiral carbon that is bonded to four different groups (e.g., chlorine, hydrogen, CH2, and another carbon).
- There is no plane of symmetry.
- Therefore, this molecule is optically active and can rotate plane-polarized light.

### Step 3: Analyze the third molecule
- Again, identify the carbon atoms and their substituents.
- Check for chiral carbon and plane of symmetry.

**Conclusion for third molecule**:
- Although there is a carbon with four bonds, there is a plane of symmetry present.
- Therefore, it is not optically active and cannot rotate plane-polarized light.

### Step 4: Analyze the fourth molecule
- Check for chiral carbon and plane of symmetry.

**Conclusion for fourth molecule**:
- The carbon atoms do not have four different substituents.
- Therefore, it is not optically active and cannot rotate plane-polarized light.

### Final Answer:
The second molecule is the only one that is expected to rotate plane-polarized light.

---