Electrophiles are defined as

• A. Electron pair acceptors
• B. Electron pair donors
• C. Nucleophiles
• D. Bases

Answer: (A)

Electrophiles are electron pair acceptors. They are electron-poor species that attract an electron pair from another molecule to form a bond, acting as Lewis acids. In a reaction, a nucleophile donates a lone pair to the electrophile. For example, a proton accepts electron density from a base like water or ammonia, and the carbon atom in a polarized carbonyl group becomes electrophilic and can be attacked by a nucleophile. This contrasts with nucleophiles (electron pair donors) and bases (proton acceptors, or electron pair donors in Lewis terms). So the description that fits best is electron pair acceptors.