Which of the following compound is not used as fertilizer

Options

A. Ammonium sulphate
B. Urea
C. Calcium super phosphate
D. `Ca_(3)(PO_(4))_(2)`

Answer

To determine which of the following compounds is not used as a fertilizer, we need to analyze each option provided.

### Step-by-Step Solution:

1. **Identify the Compounds**:
We will consider the four compounds given in the question. Let's assume they are:
- Ammonium sulfate (NH₄)₂SO₄
- Urea (CH₄N₂O)
- Calcium superphosphate (Ca(H₂PO₄)₂)
- Tricalcium phosphate (Ca₃(PO₄)₂)

2. **Analyze Ammonium Sulfate**:
- **Molecular Formula**: (NH₄)₂SO₄
- **Usage**: Ammonium sulfate is used as a fertilizer because it provides nitrogen, which is essential for plant growth. It increases the concentration of nitrogen in the soil.

3. **Analyze Urea**:
- **Molecular Formula**: CH₄N₂O
- **Usage**: Urea is one of the most important nitrogen fertilizers. It is widely used to enhance nitrogen levels in the soil, promoting plant growth.

4. **Analyze Calcium Superphosphate**:
- **Molecular Formula**: Ca(H₂PO₄)₂
- **Usage**: Calcium superphosphate is a significant source of phosphorus for plants. It is one of the first chemical fertilizers used and helps in improving crop yield.

5. **Analyze Tricalcium Phosphate**:
- **Molecular Formula**: Ca₃(PO₄)₂
- **Usage**: Tricalcium phosphate is not used as a fertilizer because the phosphorus it contains is insoluble in water. Plants cannot absorb insoluble phosphorus, making it ineffective as a fertilizer.

6. **Conclusion**:
- Based on the analysis, the compound that is not used as a fertilizer is **Tricalcium Phosphate (Ca₃(PO₄)₂)** because it contains insoluble phosphorus.

### Final Answer:
The compound that is not used as a fertilizer is **Tricalcium Phosphate (Ca₃(PO₄)₂)**.