Which one of the following does not contain centre of sysmmetry?

Options

A.
B.
C.
D.

Answer

To determine which of the given options does not contain a center of symmetry, we first need to understand what a center of symmetry is. A center of symmetry (or inversion center) is a point in a molecule such that for any atom at position (x, y, z), there is an identical atom at the position (-x, -y, -z). This means that if you were to draw a line through the center, the parts of the molecule on either side of the center would be mirror images of each other.

### Step-by-Step Solution:

1. **Understand the Concept of Center of Symmetry:**
- A center of symmetry exists if you can find a point in the molecule such that for every component on one side, there is an identical component on the opposite side.

2. **Analyze Each Option:**
- **Option A (Naphthalene):**
- Naphthalene has a structure that allows it to be divided into two equal halves through a center point. Therefore, it has a center of symmetry.
- **Option B:**
- In this option, all constituents are located in the same plane. Since there are no components above or below the plane, it cannot be divided into two equal halves through a center point. Thus, it does not have a center of symmetry.
- **Option C:**
- This option has components both above and below the plane, allowing it to be divided into two equal halves through a center point. Therefore, it has a center of symmetry.
- **Option D:**
- Similar to option C, this option also has components above and below the plane, allowing for a division into equal halves. Thus, it has a center of symmetry.

3. **Conclusion:**
- After analyzing all options, we find that **Option B** is the only one that does not contain a center of symmetry because all its constituents lie in the same plane.

### Final Answer:
**Option B does not contain a center of symmetry.**