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🧪 Chemistry  ·  Redox Reactions  ·  NEET & JEE

For a spontaneous redox reaction, the standard cell potential E°<sub>cell</sub> and ΔG° must be, respectively:

Answer: Positive and negative.

  • A Positive and positive
  • B Negative and negative
  • C Positive and negative
  • D Negative and positive

Correct answer: C. Positive and negative

Explanation: ΔG° = −nFE°<sub>cell</sub>; spontaneity requires ΔG° < 0, which needs E°<sub>cell</sub> > 0.

Electron Transfer: Zn + Cu²⁺ → Zn²⁺ + CuZnloses 2e⁻OXIDISED (Zn → Zn²⁺)2e⁻Cu²⁺gains 2e⁻REDUCED (Cu²⁺ → Cu)Zn = reducing agentCu²⁺ = 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.

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