Aromatic hydrocarbons undergo

Options

A. Nucleophilic addition reactions
B. Electrophilic addition reactions
C. Electrophilic substituion reactions
D. All of these.

Answer

To answer the question regarding the reactions that aromatic hydrocarbons undergo, we can break down the solution into clear steps:

### Step-by-Step Solution:

1. **Understanding Aromatic Hydrocarbons**:
- Aromatic hydrocarbons are cyclic compounds that contain conjugated double bonds and exhibit resonance. A common example is benzene, which has a stable ring structure due to the delocalization of pi electrons.

2. **Identifying the Nature of Reactions**:
- Aromatic hydrocarbons are characterized by their stability and unique electron cloud formed by the delocalized pi electrons. This electron cloud has a higher electron density, making it susceptible to attack by electrophiles (electron-loving species).

3. **Evaluating Reaction Types**:
- **Nucleophilic Addition Reactions**: These reactions are not typical for aromatic compounds because they would disrupt the aromatic stability by breaking the double bonds.
- **Electrophilic Addition Reactions**: Similar to nucleophilic addition, these reactions would also disturb the aromatic character, making them unfavorable.
- **Electrophilic Substitution Reactions**: This type of reaction is common for aromatic compounds. Here, an electrophile replaces one of the hydrogen atoms in the aromatic ring without disrupting the overall aromatic stability.

4. **Example of Electrophilic Substitution**:
- A classic example is the chlorination of benzene. In this reaction, chlorine (Cl2) reacts with benzene in the presence of a catalyst (like AlCl3). The chlorine molecule forms a complex with the catalyst, allowing one chlorine atom to substitute for a hydrogen atom on the benzene ring, forming chlorobenzene and releasing HCl.

5. **Conclusion**:
- Based on the analysis, aromatic hydrocarbons primarily undergo electrophilic substitution reactions. Therefore, the correct answer to the question is that aromatic hydrocarbons undergo **electrophilic substitution reactions**.

### Final Answer:
Aromatic hydrocarbons undergo **electrophilic substitution reactions**.