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Wednesday, 10 June 2026
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Chemistry Past Questions and Answers

Jamb 2005 Chemistry Questions

Question 6:
In which of the following reactions can the oxidation number of the nitrogen be said to have increased?
  • A 2NO<sub style='font-size: smaller;'>(g)</sub> + O<sub style='font-size: smaller;'>2(g)</sub> → 2NO<sub style='font-size: smaller;'>2(g)</sub>
  • B NO<sub style='font-size: smaller;'>(g)</sub> + Cl<sub style='font-size: smaller;'>2(g)</sub> → NOCl<sub style='font-size: smaller;'>2(l)</sub>
  • C FeSO<sub style='font-size: smaller;'>4(aq)</sub> + NO<sub style='font-size: smaller;'>(g)</sub> → Fe(NO)SO<sub style='font-size: smaller;'>4(s)</sub>
  • D NO<sub style='font-size: smaller;'>(g)</sub> + Br<sub style='font-size: smaller;'>2(l)</sub> → NOBr<sub style='font-size: smaller;'>2(l)</sub>
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Question 7:
2H2 + O22 → H2+O ΔH = -571kJ
In the equation above, how much heat will be liberated if 12.0g of hydrogen is burnt in excess oxygen?
  • A -1142 kJ
  • B -571 kJ
  • C +1142 kJ
  • D -1713 kJ
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Question 8:
A concentrated solution containing H+, Cu2+, OH- and Cl- was electrolyzed using platinum electrodes.
The ion that will be discharged at the cathode is
  • A Cu<sup style='font-size: smaller;'>2+</sup>
  • B Cl<sup style='font-size: smaller;'>-</sup>
  • C H<sup style='font-size: smaller;'>+</sup>
  • D OH<sup style='font-size: smaller;'>-</sup>
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Question 9:
When sulphur (IV) oxide is passed into a solution of sodium hydroxide for a long time, it eventually produces a solution of
  • A NaHSO<sub style='font-size: smaller;'>4</sub>
  • B Na<sub style='font-size: smaller;'>2</sub>SO<sub style='font-size: smaller;'>3</sub>
  • C NaHSO<sub style='font-size: smaller;'>3</sub>
  • D Na<sub style='font-size: smaller;'>2</sub>SO<sub style='font-size: smaller;'>4</sub>
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Question 10:
What is the correct IUPAC name for NO\(_{2} ^{-}\)?
  • A Dioxonitrate (IV) ion
  • B Trioxonitrate (III) ion
  • C Trioxonitrate (IV) ion
  • D Dioxonitrate (III) ion
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