Answer: Disproportionation of Cl 2.
- A Simple oxidation
- B Disproportionation of Cl<sub>2</sub>
- C Electrolysis
- D Acid-base neutralisation only
Correct answer: B. Disproportionation of Cl<sub>2</sub>
Explanation: Cl₂ (oxidation state 0) produces NaCl (Cl is -1, reduced) and NaOCl (Cl is +1, oxidised). The same element undergoes both oxidation and reduction: disproportionation.
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.