Which of the following statement is correct ?

Options

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

Answer

To determine the correct statement about H3PO3 (phosphorous acid), we need to analyze its properties step by step.

### Step 1: Identify the Structure of H3PO3
H3PO3, or phosphorous acid, has the following structure:
- It consists of one phosphorus (P) atom, three oxygen (O) atoms, and three hydrogen (H) atoms.
- The structure can be represented as:
- P is bonded to one double-bonded oxygen (O=) and two hydroxyl groups (–OH).
- The third hydrogen atom is directly bonded to phosphorus.

### Step 2: Determine the Basicity of H3PO3
- Basicity refers to the number of replaceable hydrogen ions (H+) in an acid.
- In H3PO3, there are two hydroxyl groups (–OH) that can release H+ ions.
- Thus, H3PO3 is classified as a **dibasic acid** because it can donate two protons.

### Step 3: Assess the Reducing Property of H3PO3
- A reducing agent is a substance that can donate electrons in a chemical reaction.
- H3PO3 can reduce certain metal ions, such as Cu²⁺ (copper ions), to their elemental form (Cu).
- The reaction can be represented as:
- H3PO3 + CuSO4 → Cu + H2SO4
- In this reaction, H3PO3 donates electrons, indicating that it acts as a reducing agent.

### Step 4: Evaluate the Given Statements
Now, let's evaluate the provided options based on our analysis:
1. H3PO3 is tribasic and reducing. **(Incorrect)**
2. H3PO3 is tribasic and non-reducing. **(Incorrect)**
3. H3PO3 is dibasic and non-reducing. **(Incorrect)**
4. H3PO3 is dibasic and reducing. **(Correct)**

### Conclusion
The correct statement is that H3PO3 is **dibasic and reducing**.

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