Answer: Oxidised.
- A Oxidised
- B Reduced
- C Not involved in the redox
- D Acting as a reducing agent
Correct answer: A. Oxidised
Explanation: Oxygen in H₂O has oxidation state -2; in O₂ it is 0. It loses electrons and is oxidised (goes to higher, less negative oxidation state).
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.