Assertion : `H_(3)BO_(3)` is a weak acid.
Reason : Water extracts the proton of `H_(3)BO_(3)`.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Answer

To solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that `H3BO3` (orthoboric acid) is a weak acid.
- This is true because `H3BO3` has a low dissociation constant (Ka = 5.6 × 10^(-10)), indicating that it does not completely dissociate in solution, which is characteristic of weak acids.

2. **Understanding the Reason**:
- The reason states that water extracts the proton from `H3BO3`.
- This statement is misleading. While `H3BO3` can interact with water, it does not behave as a typical proton donor (like strong acids do). Instead, `H3BO3` acts more like a Lewis acid, where it accepts a lone pair of electrons from water rather than donating a proton.

3. **Conclusion**:
- The assertion is correct: `H3BO3` is indeed a weak acid.
- The reason is incorrect: water does not extract a proton from `H3BO3` in the way the reason suggests. Instead, `H3BO3` interacts with water by accepting electron pairs.

4. **Final Answer**:
- Since the assertion is true and the reason is false, the correct conclusion is that the assertion is true, but the reason is false.