Answer: Oxidised.
- A Reduced
- B Oxidised
- C Acting as an oxidising agent
- D Unchanged
Correct answer: B. Oxidised
Explanation: Magnesium goes from oxidation state 0 to +2 in MgO; it loses electrons and is oxidised.
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.