Answer: Increases.
- A Decreases
- B Remains unchanged
- C Increases
- D Becomes zero
Correct answer: C. Increases
Explanation: The reduction potential of the MnO₄⁻/Mn²⁺ couple increases with acidity (Nernst equation; H⁺ is a reactant). More acidic conditions make KMnO₄ a stronger oxidising agent.
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.