The logical sequence of nitrogen fixation in air is

Options

A. `N_2 to NH_3 to NO_2 to NO_3`
B. `NH_3 to NO to NO_2 toNO_3`
C. `NO to NO_2 to NO_3 to NH_3`
D. `N_2O to NO to NO_2 to NO_3`

Answer

### Step-by-Step Solution for the Logical Sequence of Nitrogen Fixation in Air

1. **Understanding Nitrogen Fixation**:
- Nitrogen fixation is the process where atmospheric nitrogen (N2) is converted into a form that can be used by living organisms. This process is crucial for the nitrogen cycle.

2. **Identify the Source of Nitrogen**:
- The atmosphere consists of approximately 78% nitrogen gas (N2). This nitrogen is the starting point for the fixation process.

3. **Conversion of Nitrogen Gas (N2)**:
- The first step in nitrogen fixation involves the conversion of nitrogen gas (N2) into ammonia (NH3). This can occur through biological fixation (e.g., by nitrogen-fixing bacteria) or physical processes (e.g., lightning).

4. **Formation of Nitrites (NO2-)**:
- After ammonia (NH3) is produced, certain bacteria, such as Nitrosomonas, convert ammonia into nitrites (NO2-).

5. **Formation of Nitrates (NO3-)**:
- Subsequently, nitrites (NO2-) are further converted into nitrates (NO3-) by another group of bacteria known as Nitrobacter.

6. **Final Sequence**:
- The logical sequence of nitrogen fixation in the air can be summarized as:
- **N2 (Nitrogen gas) → NH3 (Ammonia) → NO2- (Nitrites) → NO3- (Nitrates)**

### Conclusion
The correct logical sequence of nitrogen fixation in the air is: **N2 → NH3 → NO2- → NO3-**.