Which term describes a compound that can accept both electron pairs and protons?

• A. Bronsted-Lowry
• B. Amphiprotic species
• C. Amphoteric species
• D. Polyprotic acid

Answer: (C)

This item is about substances that can play either role in a reaction depending on what they encounter. Amphoteric species can act as both acids and bases in different contexts. That means they can accept protons (behaving as Bronsted bases) and they can accept electron pairs (behaving as Lewis acids) depending on the reaction partner. The description—accepting both electron pairs and protons—maps directly to this flexible behavior, so amphoteric is the best fit. Water and many metal oxides are classic examples, since they can react with both acids and bases. In contrast, focusing only on proton transfer points to Bronsted-Lowry bases or amphiprotic behavior, and polyprotic acid describes acids with multiple removable protons, not this dual capability.