In the reaction, `P_2 O_5 + 3 CaO to Ca_3 (PO_4)_2, P_2 O_5` acts as….

Options

A. Acidic flux
B. Basic flux
C. Basic impurity
D. Acidic impurity

Answer

To determine how \( P_2O_5 \) acts in the reaction \( P_2O_5 + 3 CaO \rightarrow Ca_3(PO_4)_2 \), we can analyze the components of the reaction step by step.

### Step-by-Step Solution:

1. **Identify the Reactants and Products**:
- The reactants are \( P_2O_5 \) (phosphorus pentoxide) and \( CaO \) (calcium oxide).
- The product is \( Ca_3(PO_4)_2 \) (calcium phosphate).

2. **Understand the Nature of \( P_2O_5 \)**:
- \( P_2O_5 \) is known to be an acidic oxide. It can react with bases to form salts. In this case, it reacts with \( CaO \), which is a basic oxide.

3. **Analyze the Reaction**:
- In the reaction, \( P_2O_5 \) combines with \( CaO \) to form \( Ca_3(PO_4)_2 \). This indicates that \( P_2O_5 \) is contributing to the formation of a phosphate compound.

4. **Determine the Role of \( P_2O_5 \)**:
- Since \( P_2O_5 \) is an acidic oxide and it reacts with a base (calcium oxide), it acts as an acid in this reaction.

5. **Conclusion**:
- Therefore, \( P_2O_5 \) acts as an acidic impurity in the reaction with \( CaO \) to form \( Ca_3(PO_4)_2 \).

### Final Answer:
In the reaction \( P_2O_5 + 3 CaO \rightarrow Ca_3(PO_4)_2 \), \( P_2O_5 \) acts as an **acidic impurity**.