Answer: Li.
- A Cu
- B Zn
- C Li
- D Na
Correct answer: C. Li
Explanation: Standard reduction potential: Li⁺/Li = -3.04 V (most negative), meaning Li has the greatest tendency to lose electrons and is the strongest reducing agent.
Electron transfer in a redox reaction: zinc loses electrons (oxidised, acts as reducing agent) and copper(II) ions gain those same electrons (reduced, acts as oxidising agent).
Concept context
Master electron transfer in chemistry: assign oxidation states, balance half-reactions, identify oxidising and reducing agents, and connect redox to everyday reactions.