Which of the following oxy anion(s) contain(s) P-O bond order equal to 1.5?

Options

A. `H_(2)P_(2)O_(6)^(2-)`
B. `H_(2)PO_(3)^(-)`
C. `H_(2)PO_(4)^(-)`
D. `H_(2)PO_(2)^(-)`

Explanation

To determine which of the given oxyanions contains a P-O bond order equal to 1.5, we will analyze the structures of each oxyanion and calculate their bond orders step by step.

### Step 1: Analyze the oxyanions

We have the following oxyanions to consider:
1. H₂P₂O₆²⁻
2. H₂PO₃⁻
3. H₂PO₄⁻
4. H₂PO₂⁻

### Step 2: Draw the structures and determine bond orders

#### a. H₂P₂O₆²⁻
- Structure:
- Two phosphorus atoms connected by a single bond.
- Each phosphorus has one double bond with oxygen and two single bonds with negatively charged oxygen atoms and hydroxyl groups.

- Total bonds:
- P-P (1 sigma) + 2 P=O (2 double bonds) + 4 P-O (4 single bonds) = 1 + 2 + 4 = 7 bonds.

- Sigma bonds:
- 1 (P-P) + 2 (P=O) + 4 (P-O) = 7 sigma bonds.

- Bond order = Total bonds / Sigma bonds = 7 / 6 = 1.17.

#### b. H₂PO₃⁻
- Structure:
- One phosphorus atom with one double bond to oxygen and one single bond to an oxygen with a negative charge, and one hydroxyl group.

- Total bonds:
- P=O (1 double bond) + 2 P-O (2 single bonds) = 1 + 2 = 3 bonds.

- Sigma bonds:
- 1 (P=O) + 2 (P-O) = 3 sigma bonds.

- Bond order = Total bonds / Sigma bonds = 3 / 3 = 1.

#### c. H₂PO₄⁻
- Structure:
- One phosphorus atom with one double bond to oxygen and three single bonds to oxygen (one of which is a hydroxyl).

- Total bonds:
- P=O (1 double bond) + 3 P-O (3 single bonds) = 1 + 3 = 4 bonds.

- Sigma bonds:
- 1 (P=O) + 3 (P-O) = 4 sigma bonds.

- Bond order = Total bonds / Sigma bonds = 4 / 4 = 1.

#### d. H₂PO₂⁻
- Structure:
- One phosphorus atom with one double bond to oxygen and one single bond to an oxygen with a hydroxyl group and another single bond to a hydrogen.

- Total bonds:
- P=O (1 double bond) + 2 P-O (2 single bonds) = 1 + 2 = 3 bonds.

- Sigma bonds:
- 1 (P=O) + 2 (P-O) = 3 sigma bonds.

- Bond order = Total bonds / Sigma bonds = 3 / 2 = 1.5.

### Conclusion
The oxyanion that contains a P-O bond order equal to 1.5 is **H₂PO₂⁻**.