Diprotic compound among the following are

Options

A. `H_3PO_3`
B. `H_3PO_2`
C. `HClO_3`
D. `HPO_3`

Answer

To determine which of the given compounds is diprotic, we need to identify how many hydrogen ions (H⁺) each compound can donate in solution. A diprotic compound is defined as one that can donate two protons (H⁺ ions).

### Step-by-Step Solution:

1. **Identify the Compounds**: The compounds given are:
- H₃PO₃ (Phosphorous acid)
- H₃PO₂ (Phosphorous acid)
- HClO₃ (Chloric acid)
- HPO₃ (Phosphoric acid)

2. **Define Diprotic Compounds**: A diprotic compound can donate two protons (H⁺ ions) in solution. Therefore, we need to analyze the structure of each compound to see how many H⁺ ions can be released.

3. **Analyze Each Compound**:
- **H₃PO₃**: This compound has three hydrogen atoms. The structure shows that two of these hydrogens are attached to oxygen (as hydroxyl groups), allowing it to donate two H⁺ ions. Thus, H₃PO₃ is a diprotic compound.
- **H₃PO₂**: This compound has three hydrogen atoms, but only one hydrogen is attached to oxygen. Therefore, it can only donate one H⁺ ion, making it a monoprotic compound.
- **HClO₃**: This compound has one hydrogen atom attached to oxygen. It can donate only one H⁺ ion, thus it is also a monoprotic compound.
- **HPO₃**: This compound has only one hydrogen atom attached to oxygen, so it can also donate only one H⁺ ion, making it a monoprotic compound.

4. **Conclusion**: Based on the analysis, the only diprotic compound among the options is H₃PO₃.

### Final Answer:
The diprotic compound among the given options is **H₃PO₃**.