Answer: Reduced from 0 to -1.
- A Oxidised from -1 to 0
- B Reduced from 0 to -1
- C Acting as reducing agent
- D Undergoing disproportionation
Correct answer: B. Reduced from 0 to -1
Explanation: F₂ contains F at 0; in HF, F is -1. F₂ gains electrons (reduction) and is the oxidising agent. Oxygen in H₂O is oxidised from -2 to 0 in O₂.
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.