The oxyacid of phosphorous which has more non-ionisable hydrogens

Options

A. `H_(3)PO_(2)`
B. `H_(3)PO_(3)`
C. `H_(3)PO_(4)`
D. `H_(3)PO_(5)`

Answer

To determine the oxyacid of phosphorus that has the most non-ionizable hydrogens, we will analyze the structures of the given oxyacids and count the number of non-ionizable hydrogens in each.

### Step-by-Step Solution:

1. **Understand Non-Ionizable Hydrogens**:
Non-ionizable hydrogens are those that are directly bonded to the phosphorus atom (P) and are not part of hydroxyl (OH) groups.

2. **Analyze Each Oxyacid**:
- **H₃PO₂ (Phosphorous Acid)**:
- Structure: P is double bonded to O, and has two H atoms directly bonded to it, along with one OH group.
- Non-ionizable H count: 2 (the two H atoms directly bonded to P).

- **H₃PO₃ (Phosphoric Acid)**:
- Structure: P is double bonded to O, and has one H atom directly bonded to it, along with two OH groups.
- Non-ionizable H count: 1 (the one H atom directly bonded to P).

- **H₃PO₄ (Phosphoric Acid)**:
- Structure: P is double bonded to O, and has three OH groups.
- Non-ionizable H count: 0 (no H atoms directly bonded to P).

- **H₃PO₅ (Perphosphoric Acid)**:
- Structure: P is double bonded to O, and has four OH groups.
- Non-ionizable H count: 0 (no H atoms directly bonded to P).

3. **Compare the Counts**:
- H₃PO₂: 2 non-ionizable H
- H₃PO₃: 1 non-ionizable H
- H₃PO₄: 0 non-ionizable H
- H₃PO₅: 0 non-ionizable H

4. **Conclusion**:
The oxyacid of phosphorus with the most non-ionizable hydrogens is **H₃PO₂** (Phosphorous Acid) with 2 non-ionizable hydrogens.

### Final Answer:
The oxyacid of phosphorus which has more non-ionizable hydrogens is **H₃PO₂**.