Question

Which of the following statements is correct regarding boric acid?

• A. It acts as a weak Lewis acid by accepting \( OH^- \) from water.
• B. It is a proton donor acid.
• C. It is a strong tribasic acid.
• D. It behaves as a Brønsted-Lowry acid in aqueous solution.
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Hint:

- Boric acid is a Lewis acid, not a Brønsted acid.
- It reacts with water by accepting \( OH^- \), forming \( [B(OH)_4]^- \).
- Unlike typical acids, it does not directly release \( H^+ \).

Answer 1

The Correct Option is A

Step 1: Understanding the Nature of Boric Acid
- Boric acid (\( H_3BO_3 \)) is a weak monobasic acid.
- It does not donate protons (not a Brønsted-Lowry acid).
- Instead, it acts as a Lewis acid by accepting \( OH^- \) ions from water.
Step 2: Reaction of Boric Acid in Water
\[ H_3BO_3 + H_2O \rightarrow [B(OH)_4]^- + H^+ \] - In this reaction, boric acid accepts OH\( ^- \) from water, leading to the release of \( H^+ \) ions indirectly.
- This confirms that boric acid acts as a weak Lewis acid.
Step 3: Analyzing the Given Options
- (1) It acts as a weak Lewis acid by accepting \( OH^- \) from water. Correct.
- (2) It is a proton donor acid. Incorrect, because it does not directly donate protons.
- (3) It is a strong tribasic acid. Incorrect, as it is weak and monobasic, not tribasic.
- (4) It behaves as a Brønsted-Lowry acid in aqueous solution. Incorrect, as it does not donate \( H^+ \) directly.
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