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Sunday, 14 June 2026
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Chemistry Past Questions and Answers

Jamb 1984 Chemistry Questions

Question 11:
In which of the following reactions does hydrogen peroxide act as a reducing agent?
  • A H<sub style='font-size: smaller;'>2</sub>S + H<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>2</sub> \(\to\) S + 2H<sub style='font-size: smaller;'>2</sub>O
  • B PbSO<sub style='font-size: smaller;'>3</sub> + H<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>2</sub> \(\to\) PbSO<sub style='font-size: smaller;'>4</sub> + H<sub style='font-size: smaller;'>2</sub>O
  • C 2I+ 2H<sup style='font-size: smaller;'>+</sup> + H<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>2</sub> \(\to\) I<sub style='font-size: smaller;'>2</sub> + 2H<sub style='font-size: smaller;'>2</sub>O
  • D PbO<sub style='font-size: smaller;'>2</sub> + 2HNO<sub style='font-size: smaller;'>3</sub> + H<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>2</sub> \(\to\) Pb(NO<sub style='font-size: smaller;'>3</sub>)<sub style='font-size: smaller;'>2</sub> + 2H<sub style='font-size: smaller;'>2</sub>O + O<sub style='font-size: smaller;'>2</sub>
  • E SO<sub style='font-size: smaller;'>2</sub> + H<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>2</sub> \(\to\) H<sub style='font-size: smaller;'>2</sub>SO<sub style='font-size: smaller;'>4</sub>
View Answer & Explanation
Question 12:
For the reaction 2Fe3+ 2I- \(\to\) 2Fe2+ + I2, which of the following statements is TRUE?
  • A Fe is oxidized to Fe<sup style='font-size: smaller;'>3+</sup>
  • B Fe<sup style='font-size: smaller;'>3+</sup> is oxidized to Fe<sup style='font-size: smaller;'>2+</sup>
  • C I<sup style='font-size: smaller;'>-</sup> is oxidized to I<sub style='font-size: smaller;'>2</sub>
  • D I<sup style='font-size: smaller;'>-</sup> is reduced to I<sub style='font-size: smaller;'>2</sub>
  • E I<sup style='font-size: smaller;'>-</sup> is displacing an electron from Fe<sup style='font-size: smaller;'>3+</sup>
View Answer & Explanation
Question 13:
In dilute solution the heat of the reaction NaOH + HCl = NaCl + H2O is - 57.3kJ. Therefore the heat of the reaction 2NaOH + H2SO4 \(\to\) Na2SO4 + 2H2O is
  • A + 28.65 kJ
  • B - 28.65KJ
  • C + 57.3KJ
  • D - 114.6 KJ
  • E - 229.2 KJ
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Question 14:
Which of the following methods may be used to prepare trioxonitrate (V) acid (nitric acid) in the laboratory?
  • A Heating ammonia gas with tetraoxosulphate (VI) acid
  • B Heating ammonium trioxonitrate (V) with tetraoxosulphate (VI) acid
  • C Heating sodium trioxonitrate (V) with tetraoxosulphate (VI) acid
  • D Heating potassium trioxonitrate (V) with calcium hydroxide
  • E Heating a mixture of ammonia gas and oxygen.
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Question 15:
Lime - water, which is used in the laboratory for the detection of carbon(iv)oxide is an aqueous solution of
  • A Ca(OH)<sub style='font-size: smaller;'>2</sub>
  • B CaCO<sub style='font-size: smaller;'>3</sub>
  • C CaHCO<sub style='font-size: smaller;'>3</sub>
  • D CaSO<sub style='font-size: smaller;'>4</sub>
  • E N<sub style='font-size: smaller;'>2</sub>CO<sub style='font-size: smaller;'>3</sub>
View Answer & Explanation