Which one of the following oxides is ionic ?

Options

A. `Al_(2)`
B. `MnO_(2)`
C. `P_(2)O_(6)`
D. `CrO_(3)`

Answer

To determine which one of the following oxides is ionic, we will analyze the electronegativity differences between the elements in each oxide. The options given are Al2O3, MnO2, P2O6, and CrO3.

### Step-by-Step Solution:

1. **Identify the Oxides**: The oxides we need to analyze are:
- Al2O3
- MnO2
- P2O6
- CrO3

2. **Analyze Al2O3**:
- Aluminum (Al) has an electronegativity of approximately 1.61.
- Oxygen (O) has an electronegativity of approximately 3.44.
- Calculate the difference:
\[ \text{Difference} = |1.61 - 3.44| = 1.83 \]
- Since the difference is greater than 1.7, Al2O3 is ionic.

3. **Analyze MnO2**:
- Manganese (Mn) has an electronegativity of approximately 1.55.
- Oxygen (O) has an electronegativity of approximately 3.44.
- Calculate the difference:
\[ \text{Difference} = |1.55 - 3.44| = 1.89 \]
- Since the difference is greater than 1.7, MnO2 is ionic.

4. **Analyze P2O6**:
- Phosphorus (P) has an electronegativity of approximately 2.19.
- Oxygen (O) has an electronegativity of approximately 3.44.
- Calculate the difference:
\[ \text{Difference} = |2.19 - 3.44| = 1.25 \]
- Since the difference is less than 1.7, P2O6 is covalent.

5. **Analyze CrO3**:
- Chromium (Cr) has an electronegativity of approximately 1.66.
- Oxygen (O) has an electronegativity of approximately 3.44.
- Calculate the difference:
\[ \text{Difference} = |1.66 - 3.44| = 1.78 \]
- Since the difference is greater than 1.7, CrO3 is ionic.

6. **Conclusion**:
- From the analysis, we find that:
- Al2O3: Ionic
- MnO2: Ionic
- P2O6: Covalent
- CrO3: Ionic
- Therefore, the oxides that are ionic are Al2O3, MnO2, and CrO3. However, since the question asks for one, we can conclude that MnO2 is the most straightforward example of an ionic oxide.

### Final Answer:
The ionic oxide among the given options is **MnO2**.