Which of the following has P-P linkage ?

Options

A. `H_(4) P_(2) O_(6)`
B. `H_(4) P_(2) O_(7)`
C. `HPO_(3)`
D. `H_(3) PO_(4)`

Answer

To determine which of the given compounds has a P-P (phosphorus-phosphorus) linkage, we will analyze the structures of the provided options.

### Step-by-step Solution:

1. **Identify the Compounds**: The compounds given are:
- Option 1: H₄P₂O₆ (Hypophosphoric Acid)
- Option 2: H₄P₂O₇ (Pyrophosphoric Acid)
- Option 3: HPO₃ (Metaphosphoric Acid)
- Option 4: H₃PO₄ (Orthophosphoric Acid)

2. **Draw the Structures**:
- **H₄P₂O₆**: The structure can be drawn as follows:
- It has two phosphorus atoms (P) connected to each other with a single bond, and each phosphorus is bonded to hydroxyl (OH) groups and oxygen atoms.
- The structure shows a P-P bond.

- **H₄P₂O₇**: This compound also contains two phosphorus atoms, but they are linked through an oxygen atom (P-O-P linkage), not a direct P-P bond.

- **HPO₃**: This compound contains only one phosphorus atom and does not have a P-P bond.

- **H₃PO₄**: This is orthophosphoric acid, which also contains only one phosphorus atom and does not exhibit a P-P bond.

3. **Analyze the Linkages**:
- In **H₄P₂O₆**, the direct bond between the two phosphorus atoms indicates a P-P linkage.
- In **H₄P₂O₇**, **HPO₃**, and **H₃PO₄**, there are no direct P-P linkages.

4. **Conclusion**: The only compound that has a P-P linkage is **H₄P₂O₆** (Hypophosphoric Acid).

### Final Answer:
**H₄P₂O₆ (Hypophosphoric Acid) has a P-P linkage.**