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JAMB Chemistry 1988 Question 31

Question 31

Redox Reactions

When H2S gas is passed into a solution of iron (III) chloride, the colour changes from yellow to green. This is because

  1. A.H2S is reduced to S
  2. B.Fe3+ ions are oxidized by H2S
  3. C.Fe3+ ions are oxidized by Fe2+ ions
  4. D.Fe3+ ions are reduced to Fe2+ ions.
Show the answer and explanation

Answer: D (Fe3+ ions are reduced to Fe2+ ions.)

Explanation

H2S is a reducing agent: it reduces yellow Fe3+ to green Fe2+ and is itself oxidised to sulphur.