`P-P` linkage is present in

Options

A. Pyrophosphoric acid
B. Hypophosphoric acid
C. Peroxy phosphoric acid
D. Metaphosphoric acid

Answer

To determine where the P-P linkage is present among the given options, we will analyze the structures of each compound step by step.

### Step 1: Analyze Pyrophosphoric Acid
- **Formula**: H₄P₂O₇
- **Structure**: The structure consists of two phosphorus (P) atoms linked through oxygen atoms, but there is no direct P-P bond.
- **Conclusion**: No P-P linkage present.

### Step 2: Analyze Hypophosphoric Acid
- **Formula**: H₄P₂O₆
- **Structure**: The structure has two phosphorus atoms that are directly linked to each other.
- **Conclusion**: P-P linkage is present.

### Step 3: Analyze Peroxyphosphoric Acid
- **Formula**: H₃PO₅
- **Structure**: The structure contains phosphorus atoms, but they are not directly linked to each other.
- **Conclusion**: No P-P linkage present.

### Step 4: Analyze Metaphosphoric Acid
- **Formula**: HPO₃
- **Structure**: The structure consists of a single phosphorus atom with no direct linkage to another phosphorus atom.
- **Conclusion**: No P-P linkage present.

### Final Conclusion
After analyzing all the compounds, we find that the P-P linkage is present in **Hypophosphoric Acid (H₄P₂O₆)**.

---