Answer: Oxidation number method.
- A Ion-electron method
- B Half-reaction method
- C Oxidation number method
- D Le Chatelier method
Correct answer: C. Oxidation number method
Explanation: The oxidation number (or electron transfer) method directly tracks changes in oxidation states and adjusts stoichiometric coefficients so that the total electron gain equals the total electron loss.
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.