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Saturday, 15 August 2026
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Chemistry Past Questions and Answers

Topic: Tests for oxidizing and reducing agents

Jamb Chemistry Questions - Tests for oxidizing and reducing agents

Question 1:
In which of the following reactions is sulphur dioxide acting as an oxidizing agent?
  • A SO <sub style='font-size: smaller;'>2</sub> + 2HNO<sub style='font-size: smaller;'>3</sub> →H<sub style='font-size: smaller;'>2</sub>SO<sub style='font-size: smaller;'>4</sub> + NO<sub style='font-size: smaller;'>2</sub> + Heat
  • B 2SO<sub style='font-size: smaller;'>2</sub> + 2H<sub style='font-size: smaller;'>2</sub>O + O<sub style='font-size: smaller;'>2</sub>→ 2H<sub style='font-size: smaller;'>2</sub>SO<sub style='font-size: smaller;'>4</sub>
  • C SO<sub style='font-size: smaller;'>2</sub> + 2H<sub style='font-size: smaller;'>2</sub>O + CI<sub style='font-size: smaller;'>2</sub>→ H<sub style='font-size: smaller;'>2</sub>SO<sub style='font-size: smaller;'>4</sub> + 2HCI
  • D SO<sub style='font-size: smaller;'>2</sub> + 2H<sub style='font-size: smaller;'>2</sub>S → 3S + 2H<sub style='font-size: smaller;'>2</sub>O
  • E SO<sub style='font-size: smaller;'>2</sub> + H<sub style='font-size: smaller;'>2</sub>O → H<sub style='font-size: smaller;'>2</sub>SO<sub style='font-size: smaller;'>3</sub>
View Answer & Explanation
Question 2:
A gas that can behave as a reducing agent towards chlorine and as an oxidizing agent toward hydrogen sulphide is
  • A O<sub style='font-size: smaller;'>2</sub>
  • B NO
  • C SO<sub style='font-size: smaller;'>2</sub>
  • D NH<sub style='font-size: smaller;'>3</sub>
  • E CO<sub style='font-size: smaller;'>2</sub>
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Question 3:
2MnO-4 + 10Cl- + 16H+ → 2Mn2+ + 5Cl2 + 8H2O. Which of the substances serves as an oxidizing agent?
  • A Mn<sup style='font-size: smaller;'>2+</sup>
  • B Cl<sup style='font-size: smaller;'>-</sup>
  • C H<sub style='font-size: smaller;'>2</sub>O
  • D MnO<sup style='font-size: smaller;'>-</sup><sub style='font-size: smaller;'>4</sub>
  • E Cl<sub style='font-size: smaller;'>2</sub>
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Question 4:
Which of the following acts both s a reducing and an oxidizing agent?
  • A H<sub style='font-size: smaller;'>2</sub>
  • B SO<sub style='font-size: smaller;'>2</sub>
  • C H<sub style='font-size: smaller;'>2</sub>S
  • D C
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Question 5:
2H2S(g) + SO2(g) + H2O(I) → 3S(s) + 3H2O(I)..........(i) 3CuO(s) + 2NH3(g) → 3Cu(s) + 3H2O(I) + N2(g).........(II) In the equations above, the oxidizing agent (I) and the reducing agent in (II) respectively are?
  • A H<sub style='font-size: smaller;'>2</sub>S<sub style='font-size: smaller;'> and NH3</sub>
  • B SO<sub style='font-size: smaller;'>2</sub> and CuO
  • C SO<sub style='font-size: smaller;'>2</sub> and NH<sub style='font-size: smaller;'>3</sub>
  • D H<sub style='font-size: smaller;'>2</sub>S<sub style='font-size: smaller;'> and CuO</sub>
View Answer & Explanation