The species having no `ppi-ppi` bond but its bond order equal to that of `O_(2)^(-)`

Options

A. `ClO_(3)^(-)`
B. `PO_(4)^(3-)`
C. `SO_(4)^(2-)`
D. `XeO_(3)`

Explanation

To solve the question, we need to find a species that has no pπ-pπ bonds but has a bond order equal to that of O₂⁻. The bond order of O₂⁻ is 1.5.

### Step-by-Step Solution:

1. **Identify the Bond Order of O₂⁻:**
- The bond order of O₂⁻ can be calculated using the formula:
\[ \text{Bond Order} = \frac{\text{Number of bonding electrons} - \text{Number of antibonding electrons}}{2} \]
- For O₂, the electronic configuration is \( (σ_{1s})^2 (σ^*_{1s})^2 (σ_{2s})^2 (σ^*_{2s})^2 (σ_{2p_z})^2 (π_{2p_x})^2 (π_{2p_y})^2 (π^*_{2p_x})^1 \).
- O₂⁻ has one additional electron, which goes into the antibonding π orbital, giving it the configuration \( (π^*_{2p_x})^2 \).
- Thus, the bond order of O₂⁻ is:
\[ \text{Bond Order of O₂⁻} = \frac{10 - 4}{2} = 3 \]

2. **Identify Candidates with Bond Order of 1.5:**
- We need to find species with a bond order of 1.5 that do not have pπ-pπ bonds.
- Common candidates to consider include:
- ClO₃⁻
- SO₄²⁻
- PO₄³⁻
- XeO₃

3. **Calculate Bond Orders of Candidates:**
- **ClO₃⁻:**
- Structure: 1 Cl atom bonded to 3 O atoms (2 double bonds, 1 single bond).
- Bond Order = \( \frac{5 \text{ bonds}}{3 \text{ O atoms}} = 1.67 \) (has pπ-pπ bonds).
- **SO₄²⁻:**
- Structure: 1 S atom bonded to 4 O atoms (2 double bonds, 2 single bonds).
- Bond Order = \( \frac{6 \text{ bonds}}{4 \text{ O atoms}} = 1.5 \) (has pπ-dπ bonds).
- **PO₄³⁻:**
- Structure: 1 P atom bonded to 4 O atoms (1 double bond, 3 single bonds).
- Bond Order = \( \frac{5 \text{ bonds}}{4 \text{ O atoms}} = 1.25 \) (has pπ-pπ bonds).
- **XeO₃:**
- Structure: 1 Xe atom bonded to 3 O atoms (3 double bonds).
- Bond Order = \( \frac{6 \text{ bonds}}{3 \text{ O atoms}} = 2 \) (has pπ-pπ bonds).

4. **Conclusion:**
- The only candidate with a bond order of 1.5 and no pπ-pπ bonds is **SO₄²⁻**.

### Final Answer:
The species having no pπ-pπ bond but its bond order equal to that of O₂⁻ is **SO₄²⁻**.