Which of the following is correct ?

Options

A. `H_(3) PO_(3)` is dibasic and reducing
B. `H_(3) PO_(3)` is dibasic and non - reducing
C. `H_(3) PO_(4)` is tribasic and reducing
D. `H_(3) PO_(3)` is tribasic and non-reducing

Answer

To determine which of the statements regarding the compounds H3PO3 and H3PO4 is correct, we need to analyze their structures and properties, specifically focusing on their basicity and reducing nature.

### Step-by-Step Solution:

1. **Identify the Compounds**:
We have two compounds to analyze: H3PO3 (phosphorous acid) and H3PO4 (phosphoric acid).

2. **Analyze H3PO3 (Phosphorous Acid)**:
- **Structure**: H3PO3 has one phosphorus atom (P) double bonded to one oxygen atom (O) and is bonded to two hydroxyl groups (OH) and one hydrogen atom (H).
- **Basicity**: The presence of two hydroxyl (OH) groups indicates that H3PO3 can donate two protons (H+), making it dibasic.
- **Reducing Nature**: The presence of one H-P bond (the bond between phosphorus and hydrogen) indicates that H3PO3 can act as a reducing agent. Therefore, it is reducing in nature.

3. **Analyze H3PO4 (Phosphoric Acid)**:
- **Structure**: H3PO4 has one phosphorus atom (P) double bonded to one oxygen atom (O) and is bonded to three hydroxyl groups (OH).
- **Basicity**: The presence of three hydroxyl (OH) groups indicates that H3PO4 can donate three protons (H+), making it tribasic.
- **Reducing Nature**: H3PO4 does not have any H-P bonds, which means it cannot donate electrons effectively. Thus, it is non-reducing in nature.

4. **Match the Properties with the Statements**:
- **Statement 1**: H3PO3 is dibasic and reducing. (Correct)
- **Statement 2**: H3PO3 is dibasic and non-reducing. (Incorrect)
- **Statement 3**: H3PO4 is tribasic and reducing. (Incorrect)
- **Statement 4**: H3PO3 is tribasic. (Incorrect)

5. **Conclusion**: Based on the analysis, the correct statement is that H3PO3 is dibasic and reducing.

### Final Answer:
The correct option is: **H3PO3 is dibasic and reducing.**

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