In Lewis acid-base theory, acids are electron-pair acceptors and bases are electron-pair donors. Which term names this theory?

• A. Bronsted-Lowry
• B. Conjugate acid-base
• C. Lewis
• D. Arrhenius

Answer: (C)

This question is about the idea that acid-base behavior can be described by electron-pair transfer. In this framework, acids are electron-pair acceptors and bases are electron-pair donors, and the theory is named after Gilbert N. Lewis. It broadens the scope beyond proton transfer, so it covers reactions that don’t involve H+ at all. A classic example is ammonia donating its lone pair to boron trifluoride, forming an adduct—no protons involved, just electron-pair sharing. By contrast, Bronsted-Lowry focuses on proton transfer, Arrhenius on H+ or OH− production in solution, and the term “conjugate acid-base pair” refers to pairs formed in Brønsted-Lowry chemistry, not the naming of this theory.