The process of converting ammonia into nitrite is called

Options

A. nitrogen fixation
B. nitrogenation
C. nitrification
D. denitrification.

Explanation

To answer the question "The process of converting ammonia into nitrite is called," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Processes**: We need to identify the processes related to nitrogen and ammonia. The options given are Nitrogen fixation, Nitrogenation, Nitrification, and Denitrification.

2. **Define Each Process**:
- **Nitrogen Fixation**: This is the process where atmospheric nitrogen (N₂) is converted into ammonia (NH₃). It does not involve the conversion of ammonia to nitrite.
- **Nitrogenation**: This term refers to the process of treating a substance with nitrogen. It is not specifically related to the conversion of ammonia to nitrite.
- **Nitrification**: This is the biological process where ammonia is oxidized to nitrite (NO₂⁻) and then to nitrate (NO₃⁻). This is the process we are looking for.
- **Denitrification**: This process involves the conversion of nitrate back into nitrogen gas (N₂), which is not relevant to our question.

3. **Identify the Correct Answer**: Based on the definitions, the process that converts ammonia into nitrite is called **Nitrification**.

4. **Conclusion**: Therefore, the correct answer to the question is **Nitrification**.