Which of the following is a chemical fertilizer?

Options

A. Urea
B. Sodium
C. Ammonium sulphate
D. All of these

Answer

To determine which of the following is a chemical fertilizer, we need to identify the substances mentioned and their classifications.

### Step-by-Step Solution:

1. **Understanding Chemical Fertilizers**:
- Chemical fertilizers are substances that provide essential nutrients to plants to enhance their growth. They are typically composed of specific chemical compounds that supply nutrients like nitrogen, phosphorus, and potassium.

2. **Identifying the Options**:
- In this case, we are given two examples: urea and ammonium sulfate. We need to analyze these substances to see if they qualify as chemical fertilizers.

3. **Analyzing Urea**:
- Urea (NH₂CONH₂) is a nitrogenous fertilizer that contains about 46% nitrogen by weight. It is widely used in agriculture to promote plant growth due to its high nitrogen content, which is essential for the synthesis of proteins in plants.

4. **Analyzing Ammonium Sulfate**:
- Ammonium sulfate ((NH₄)₂SO₄) is another nitrogenous fertilizer. It contains about 21% nitrogen by weight and 24% sulfur. It is also used to provide nitrogen and sulfur to plants, making it a chemical fertilizer as well.

5. **Conclusion**:
- Both urea and ammonium sulfate are chemical fertilizers. However, if we need to select one, urea is often considered the most important nitrogenous fertilizer due to its higher nitrogen content.

### Final Answer:
- Urea is a chemical fertilizer.