Which of the following can function as Lewis acid?
Correct answer: D. I+
- A. CN-
- B. NH3
- C. CH3 - O - CH3
- D. I+
Explanation
The correct answer is I+. A Lewis acid is defined as an electron pair acceptor, and I+ fits this definition because of its positive charge and incomplete octet, making it electron-deficient. This allows it to accept electron pairs from Lewis bases. Other options, such as CN-, NH3, and CH3 - O - CH3, are more likely to donate electron pairs due to their lone pairs or negative charge, making them Lewis bases instead.
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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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