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JAMB Chemistry 1978 Question 34

Question 34

Redox Reactions

If excess zinc is added to a bluish green solution of copper(II) sulphate, and the excess zinc filtered off after completion of reaction, a colourless solution is obtained because

  1. A.both zinc and copper are metals
  2. B.the sulphate radical and the zinc ion are divalent
  3. C.zinc is more electropositive than copper
  4. D.both zinc and copper form dipositive ions in solution
  5. E.zinc is a reducing agent
Show the answer and explanation

Answer: C (zinc is more electropositive than copper)

Explanation

Zinc is higher than copper in the electrochemical series, so it displaces the blue Cu2+ ions, leaving colourless zinc sulphate solution.