An antibiotic contains nitro group attached to aromatic nucleus. It is

Options

A. penicillin
B. streptomycin
C. tetracycline
D. chloramphenicol

Explanation

To solve the question regarding which antibiotic contains a nitro group attached to an aromatic nucleus, we will analyze the structures of the given options: penicillin, streptomycin, tetracycline, and chloramphenicol.

### Step-by-Step Solution:

1. **Identify the Antibiotics**: The four options provided are:
- Penicillin
- Streptomycin
- Tetracycline
- Chloramphenicol

2. **Analyze Penicillin**:
- Penicillin has a four-membered β-lactam ring and does not contain an aromatic nucleus.
- It is characterized by a structure that includes nitrogen and sulfur but lacks a nitro group (NO2).
- **Conclusion**: Penicillin does not fit the criteria.

3. **Analyze Streptomycin**:
- Streptomycin has a complex structure with multiple rings and functional groups but does not contain an aromatic nucleus.
- It is primarily an aminoglycoside antibiotic and does not have a nitro group attached.
- **Conclusion**: Streptomycin does not fit the criteria.

4. **Analyze Tetracycline**:
- Tetracycline has a structure that includes multiple rings and hydroxyl groups, but it also does not have an aromatic nucleus with a nitro group.
- It is known for its broad-spectrum antibiotic activity but lacks the required nitro group.
- **Conclusion**: Tetracycline does not fit the criteria.

5. **Analyze Chloramphenicol**:
- Chloramphenicol has a benzene ring, which is an aromatic nucleus.
- It contains a nitro group (NO2) attached to the aromatic nucleus, along with other functional groups such as hydroxyl (OH) and amine (NH).
- **Conclusion**: Chloramphenicol fits the criteria of having a nitro group attached to an aromatic nucleus.

6. **Final Answer**:
- Based on the analysis, the antibiotic that contains a nitro group attached to an aromatic nucleus is **Chloramphenicol**.