Which one of the following is a lewis acid?
Correct answer: C. BF3
- A. (CH3)3N
- B. PH3
- C. BF3
- D. O2
Explanation
The correct answer is BF3 because it is an electron-deficient molecule with the ability to accept electron pairs, making it a Lewis acid. In contrast, (CH3)3N and PH3 are Lewis bases, as they possess lone pairs that can be donated. O2 is neither a Lewis acid nor a base because it is a stable molecule without the capability to accept or donate electron pairs in the context of Lewis acid-base reactions.
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About Bronsted-Lowry and Lewis Concepts
The Brønsted-Lowry concept defines acids as proton donors and bases as proton acceptors, producing conjugate acid-base pairs. The Lewis concept extends the idea to electron-pair acceptors and donors, so compounds such as BF3 and NH3 can be treated as acid and base even without proton transfer, unlike the Arrhenius definition.
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