Answer: Reducing agent (H2O2 is oxidised: O from -1 to 0 in O2).
- A Oxidising agent (Mn7+ → Mn2+, so KMnO4 is reduced by H2O2)
- B Reducing agent (H2O2 is oxidised: O from -1 to 0 in O2)
- C Catalyst
- D Neither oxidised nor reduced
Correct answer: B. Reducing agent (H2O2 is oxidised: O from -1 to 0 in O2)
Explanation: In this reaction, H₂O₂ is the reducing agent: O in H₂O₂ goes from -1 to 0 in O₂ (loses electrons, oxidised). KMnO₄ is the oxidising agent: Mn goes from +7 to +2 (gains electrons, reduced).
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.