Which of the following compound gives poor yield in friedel-craft reaction

Options

A.
B.
C.
D. All of these

Answer

To determine which compound gives a poor yield in the Friedel-Crafts reaction, we need to analyze the effect of different substituents on the aromatic ring. The Friedel-Crafts reaction is an electrophilic aromatic substitution reaction where an alkyl or acyl group is introduced into an aromatic ring. The key to understanding the yields in this reaction lies in the electron-donating or electron-withdrawing nature of the substituents present on the aromatic ring.

### Step-by-Step Solution:

1. **Understanding the Friedel-Crafts Reaction**:
- The Friedel-Crafts reaction involves the reaction of an aromatic compound (like benzene) with an alkyl halide in the presence of a Lewis acid catalyst (like AlCl3). The Lewis acid generates a highly reactive electrophile that can attack the aromatic ring.

2. **Identifying the Role of Substituents**:
- Substituents on the aromatic ring can either donate electron density (activating groups) or withdraw electron density (deactivating groups).
- Activating groups increase the electron density of the ring, making it more reactive towards electrophiles, while deactivating groups decrease the electron density, leading to poor yields.

3. **Analyzing the Given Compounds**:
- **Compound with Nitro Group (-NO2)**: This group has a strong -I (inductive) effect, withdrawing electron density from the ring. This leads to a poor yield in the Friedel-Crafts reaction.
- **Aniline (C6H5NH2)**: The amino group (-NH2) donates electron density to the ring, which would typically enhance reactivity. However, it can also form a complex with AlCl3, deactivating the ring and leading to poor yield.
- **Compound with Fluorine (-F)**: Fluorine is highly electronegative and exhibits a -I effect, withdrawing electron density from the ring, which also results in poor yield.
- **Conclusion**: All three substituents (nitro, amino, and fluorine) lead to poor yields in the Friedel-Crafts reaction due to their electron-withdrawing effects.

4. **Final Answer**:
- Since all the mentioned groups result in poor yields, the correct answer is that all of these compounds give poor yields in the Friedel-Crafts reaction.