Answer: H2O2.
- A KMnO4
- B F2
- C H2O2
- D K2Cr2O7
Correct answer: C. H2O2
Explanation: H₂O₂ can oxidise (reducing to H₂O, O changes from -1 to -2) or reduce (oxidising to O₂, O changes from -1 to 0), acting as both an oxidising and a reducing agent depending on the conditions.
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.