01 Redox Equilibrium
02 Carbon Compounds
03 Thermochemistry
04 Polymers
05 Consumer and Industrial Chemistry

1.1.2 Redox Reaction in Terms of Transfer of Electron

Oxidation and Reduction in Terms of Electron Transfer

  1. Oxidation occurs when a reactant loses electron.
  2. Reduction occurs when a reactant gain of electron.

Example:

CuO + Mg → Cu + MgO
In this reaction,
  1. copper (II) ion in copper(II) oxide gains 2 electrons to form copper metal.
    Half equation:
    Cu2+ + 2e → Cu

    This is a reduction process.

  2. Magnesium metal loses 2 electrons to form magnesium ions in magnesium oxide.
    Half equation:
    Mg → Mg2+ + 2e

    This is a oxidation process.

Summary

  1. Magnesium is oxidised because it loses2 electrons to form magnesium ion, Mg2+.
  2. Copper(II) oxide is reduced because copper(II) ion gains 2 electrons to form copper metal, Cu.