Which statement best pairs a species with its description?

Which statement best pairs a species with its description?

• A. Nucleophile – electron pair donor
• B. Electrophile – electron pair donor
• C. Nucleophile – electron pair acceptor
• D. Electrophile – electron pair acceptor

Answer: (A)

The key idea is the flow of electron density: a nucleophile has an electron-rich site (a lone pair or a π bond) that it can donate, so it is an electron pair donor. An electrophile, being electron-poor, accepts electrons and is an electron pair acceptor. That makes the pairing of a nucleophile with electron pair donation the best description. The other statements mix up roles: an electrophile does not donate electron pairs, and a nucleophile does not accept electron pairs. In reactions, nucleophiles attack electron-poor centers by donating their electron pair, while electrophiles attract that electron density by accepting the pair.

The key idea is the flow of electron density: a nucleophile has an electron-rich site (a lone pair or a π bond) that it can donate, so it is an electron pair donor. An electrophile, being electron-poor, accepts electrons and is an electron pair acceptor. That makes the pairing of a nucleophile with electron pair donation the best description. The other statements mix up roles: an electrophile does not donate electron pairs, and a nucleophile does not accept electron pairs. In reactions, nucleophiles attack electron-poor centers by donating their electron pair, while electrophiles attract that electron density by accepting the pair.