Which term describes a reaction in which one element takes electrons from another?

• A. Displacement
• B. Redox
• C. Oxidation-reduction
• D. Precipitation

Answer: (C)

This question tests understanding of electron transfer in redox reactions. When one element takes electrons from another, there is a transfer of electrons between species, so the overall process is a redox (oxidation–reduction) reaction. Oxidation–reduction names both halves of the process—the donor is oxidized (loses electrons) and the receiver is reduced (gains electrons)—and together they describe the actual change happening in the reaction.

The term that best describes this specific electron-transfer phenomenon is oxidation–reduction, which is also commonly shortened to redox. The shorthand redox is correct and widely used, but the full oxidation–reduction term conveys the explicit pairing of oxidation and reduction. The other options describe different reaction types: displacement involves one element pushing another out of a compound, and precipitation involves forming a solid from ions in solution, neither of which centers on electron transfer.