In chlorobenzene, chlorine is ________ but _____ directing.

Answer

To answer the question, "In chlorobenzene, chlorine is ________ but _____ directing," we need to analyze the effects of chlorine on the benzene ring.

### Step-by-Step Solution:

1. **Identify the Effects of Chlorine**:
- Chlorine has both a -I (inductive) effect and a +R (resonance) effect. The -I effect means that chlorine pulls electron density away from the benzene ring, while the +R effect means that chlorine can donate electron density through resonance.

2. **Determine the Deactivating Nature**:
- The -I effect of chlorine causes the benzene ring to be less reactive towards electrophilic substitution reactions. This means that chlorine is a deactivating group. Therefore, we can fill in the first blank: "In chlorobenzene, chlorine is **deactivating**."

3. **Determine the Directing Nature**:
- Despite being deactivating, the +R effect of chlorine allows it to stabilize the positive charge that forms during electrophilic substitution at the ortho and para positions. This means that chlorine directs incoming electrophiles to the ortho and para positions. Therefore, we can fill in the second blank: "but **ortho-para** directing."

### Final Answer:
In chlorobenzene, chlorine is **deactivating** but **ortho-para** directing.

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