Electrochemistry Class 11 Chemistry Chapter 12 Notes, MCQs & One-Liners

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  1. Electrochemistry studies the interchange of chemical and electrical energy.
  2. Electrochemical cells involve redox reactions, which are central to electrochemistry.
  3. Redox reactions involve the transfer of electrons from one species to another.
  4. Oxidation is the loss of electrons; reduction is the gain of electrons.
  5. Oxidizing agents gain electrons, whereas reducing agents lose electrons.
  6. The number of electrons lost in oxidation equals the number gained in reduction.
  7. Examples of redox processes include rusting of iron, photosynthesis, and battery operation.
  8. Electrochemical cells are studied through electrolytic and galvanic cells.
  9. Electrolytic cells use electric current to drive non-spontaneous redox reactions.
  10. Galvanic cells generate electricity from spontaneous redox reactions.
  11. Electrode potential is the ability of an electrode to push electrons through an external circuit.
  12. Standard electrode potential (E°) is measured in volts and indicates the relative tendency for reduction.
  13. The electrochemical series (ECS) arranges electrode potentials using SHE as the reference electrode.
  14. Electrodes above H₂ in the ECS have negative E°, while electrodes below H₂ have positive E°.
  15. Batteries consist of two or more galvanic cells connected in series to convert chemical energy into electrical energy.
  16. Primary cells (e.g., dry cells) are non-rechargeable, whereas secondary cells (e.g., lead-acid batteries) are rechargeable.
  17. Lead-acid batteries consist of Pb anodes and PbO₂-coated cathodes immersed in dilute H₂SO₄.
  18. The lead-acid battery reaction is: Pb + PbO₂ + 2H₂SO₄ → 2PbSO₄ + 2H₂O.
  19. Fuel cells react H₂ and O₂ to produce water and electricity, with reactants supplied continuously.
  20. Corrosion is the spontaneous oxidation of metal surfaces due to environmental factors such as O₂ and moisture.
  21. The electrochemical theory of corrosion states that metal acts as an anode and cathode, while water containing O₂ and CO₂ acts as the electrolyte.
  22. Corrosion prevention methods include painting, greasing, metal coating, and alloying.
  23. Galvanizing is the process of coating iron with zinc to prevent corrosion.
  24. Electroplating deposits metal cations onto a cathode through electrolysis (e.g., tin plating).
  25. The ion-electron method balances redox reactions by balancing electron transfer.
  26. Oxidation number (the apparent charge on an atom) is used to track electron transfer in redox reactions.
  27. E°cell = E°cathode − E°anode is the formula used to calculate cell potential.
  28. Hydrogen-oxygen fuel cells use porous carbon electrodes, a platinum catalyst, and a KOH electrolyte.