Which of the following oxide is most acidic ?

Answer

To determine which of the given oxides is the most acidic, we will analyze the oxides provided: AS2O5, P2O5, N2O5, and Sb2O5. These oxides are derived from elements in Group 15 of the periodic table.

### Step-by-Step Solution:

1. **Identify the Elements and Their Oxides**:
- The oxides in question are:
- AS2O5 (Arsenic pentoxide)
- P2O5 (Phosphorus pentoxide)
- N2O5 (Nitrogen pentoxide)
- Sb2O5 (Antimony pentoxide)

2. **Understand the Trend in Acidity**:
- In Group 15, as we move down the group from nitrogen (N) to arsenic (As) to antimony (Sb), the acidic character of the oxides generally decreases. This is due to the following reasons:
- **Electronegativity**: As we move down the group, the electronegativity of the elements decreases. Higher electronegativity typically correlates with stronger acidic behavior in oxides.
- **Metallic Character**: The metallic character increases down the group, leading to a greater basic character in the oxides. This results in a decrease in acidity.

3. **Compare the Acidity of the Oxides**:
- **N2O5**: Nitrogen is at the top of Group 15 and has the highest electronegativity, making N2O5 the most acidic.
- **P2O5**: Phosphorus is below nitrogen and has lower electronegativity than nitrogen, so P2O5 is less acidic than N2O5.
- **As2O5**: Arsenic is below phosphorus and has even lower electronegativity, making As2O5 less acidic than P2O5.
- **Sb2O5**: Antimony is at the bottom of the group and has the lowest electronegativity, making Sb2O5 the least acidic among the four.

4. **Conclusion**:
- Based on the trend of acidity in Group 15, we conclude that **N2O5 (Nitrogen pentoxide)** is the most acidic oxide among the given options.

### Final Answer:
The most acidic oxide is **N2O5**.