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Thursday, 21 May 2026
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Chemistry Past Questions and Answers

Jamb 1989 Chemistry Questions

Question 21:
An element, Z froms an anion whose formula is [Z(CN)6]y. If Z has an oxidation number of +2, what is the value of y?
  • A - 2
  • B - 3
  • C - 4
  • D - 5
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Question 22:
The combustion of ethene, C 2H 4, is given by the equation C 2H 4 + 30 2 → 2CO2 + 2H2 O; ∆H = - 1428 KJ. If the molar heats of formation of water and carbon (IV) oxide are - 286 kJ and - 396 kJ respectively, calculate the molar heat of formation of ethene in KJ
  • A - 2792
  • B + 2792
  • C - 64
  • D + 64
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Question 23:
Which of the following represents the balanced equation for the reaction of copper with concentrated trioxonitrate (V) acid?
  • A Cu <sub style='font-size: smaller;'>(s)</sub> + 2HNO <sub style='font-size: smaller;'>3(aq)</sub> → Cu (NO <sub style='font-size: smaller;'>3</sub>) <sub style='font-size: smaller;'>2(aq)</sub> + H <sub style='font-size: smaller;'>2(g)</sub>
  • B Cu <sub style='font-size: smaller;'>(s)</sub> + 4HNO <sub style='font-size: smaller;'>3(aq)</sub> → Cu (NO <sub style='font-size: smaller;'>3</sub>) <sub style='font-size: smaller;'>2(aq) </sub> + 2H <sub style='font-size: smaller;'>2</sub>O <sub style='font-size: smaller;'>(1)</sub> + 2NO <sub style='font-size: smaller;'>2(g)</sub>
  • C 3Cu <sub style='font-size: smaller;'>(s)</sub> + 8HNO<sub style='font-size: smaller;'>3(aq)</sub> → 3Cu (NO<sub style='font-size: smaller;'>3</sub>)<sub style='font-size: smaller;'>2(aq)</sub> + 4H<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>(1)</sub> + 2NO<sub style='font-size: smaller;'>(g)</sub>
  • D 3Cu<sub style='font-size: smaller;'>(s)</sub> + 4HNO<sub style='font-size: smaller;'>3(aq)</sub> → 3Cu(NO <sub style='font-size: smaller;'>3</sub>) <sub style='font-size: smaller;'>2(aq)</sub> + 2H <sub style='font-size: smaller;'>2</sub>O <sub style='font-size: smaller;'>(1)</sub> + 2NO <sub style='font-size: smaller;'>(g)</sub>
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Question 24:
The catalyst used in the contact process for the manufacture of tetraoxosulphate (VI) acid is
  • A Manganes (IV) oxide
  • B Manganese (ll) tetraoxosulphate (VI)
  • C Vanadium (V) oxide
  • D Iron metal
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Question 25:
Some products of destructive distillation of coal are
  • A Carbon (IV) oxide and ethanoic acid
  • B Trioxocarbonate (IV) acid and methanoic acid
  • C Producer gas and water gas
  • D Coke and ammonia liquor
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