In the reaction Zn + CuSO4 gives ZnSO4 + Cu, the substance oxidised is

  • A. the sulphate ion
  • B. copper ions
  • C. zinc
  • D. copper metal

Explanation

Zinc goes from an oxidation number of zero as the metal to plus 2 in the sulphate, so it has lost electrons and is oxidised, which also makes it the reducing agent. The copper ions gain those electrons, fall from plus 2 to zero and are reduced. The sulphate ion is a spectator, unchanged on both sides of the equation.

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