The chlorine atom in chlorobenzene is ortho and para direction because

Options

A. resonance effect predominates over inductive effect
B. inductive effect predominates over resonance effect
C. both inductive and resonance effect are evenly matched
D. only resonance effect and no inductive effect is operating

Answer

To understand why the chlorine atom in chlorobenzene is ortho and para directing, we can break down the explanation into clear steps.

### Step-by-Step Solution:

1. **Understanding the Structure of Chlorobenzene**:
- Chlorobenzene consists of a benzene ring with a chlorine atom attached to it. The chlorine atom is bonded to one of the carbon atoms in the benzene ring.

2. **Identifying Positions**:
- In a benzene ring, there are three types of positions relative to the substituent (chlorine in this case):
- **Ortho position**: Adjacent to the chlorine atom.
- **Meta position**: One carbon away from the chlorine atom.
- **Para position**: Opposite to the chlorine atom on the benzene ring.

3. **Resonance Effect of Chlorine**:
- Chlorine has a lone pair of electrons. This lone pair can participate in resonance with the π electrons of the benzene ring.
- When the lone pair of chlorine interacts with the benzene ring, it can donate electron density into the ring, increasing the electron density at the ortho and para positions.

4. **Formation of Resonance Structures**:
- The donation of the lone pair from chlorine leads to the formation of several resonance structures. In these structures, the negative charge can be localized at the ortho and para positions.
- This means that the ortho and para positions will have increased electron density compared to the meta position.

5. **Conclusion on Directing Effects**:
- Because the ortho and para positions have higher electron density due to resonance, the chlorine atom directs incoming electrophiles to these positions. Therefore, chlorine is considered an ortho-para director.

6. **Final Answer**:
- The chlorine atom in chlorobenzene is ortho and para directing because of the resonance effect, where the lone pair of electrons on chlorine increases electron density at the ortho and para positions.