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Saturday, 13 June 2026
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Chemistry Past Questions and Answers

Jamb 2006 Chemistry Questions

Question 41:
In which of the following is the oxidation number of sulphur equal to -2?
  • A SO<sub style='font-size: smaller;'>3</sub>
  • B S<sub style='font-size: smaller;'>8</sub>
  • C H<sub style='font-size: smaller;'>2</sub>S
  • D SO<sub style='font-size: smaller;'>2</sub>
View Answer & Explanation
Question 42:
In the electrolysis of CuSO4(g) using platinum electrodes, the reaction at the anode is
  • A 4H<sup style='font-size: smaller;'>+</sup> + 4e<sup style='font-size: smaller;'>-</sup> → 2H<sub style='font-size: smaller;'>2</sub>
  • B 4OH<sup style='font-size: smaller;'>-</sup> - 4e<sup style='font-size: smaller;'>-</sup> → 2H<sub style='font-size: smaller;'>2</sub>O + O<sub style='font-size: smaller;'>2</sub>
  • C 2OH - 2e<sup style='font-size: smaller;'>-</sup> → 2OH
  • D 2OH<sup style='font-size: smaller;'>-</sup> + 2OH<sup style='font-size: smaller;'>-</sup> → 2H<sub style='font-size: smaller;'>2</sub>O + O<sub style='font-size: smaller;'>2</sub>
View Answer & Explanation
Question 43:
Na2CO3(g) + 2HCl(aq) → 2NaCl(aq) + H2O(l) + CO2(g)
How many moles of sodium trioxocarbonate (IV) are there in a 25 cm3 solution which required 10cm3 of 0.05 mol dm-3 hydrochloric acid solution to neutralize it?
  • A 1.000 mole
  • B 0.100 mole
  • C 0.010 mole`
  • D 0.111 mole
View Answer & Explanation
Question 44:
If the heat of combustion of hydrogen is -285.8kJ,
What is the heat of formation of water?
  • A +571.6 kJ
  • B -571.6 kJ
  • C -285.8 kJ
  • D +285.8 kJ
View Answer & Explanation
Question 45:
5SO2(g) + 2KMnO4(aq) + 2H2O(l) → K2SO4 + 2MnSO4(aq) + 2H2SO4(aq)
In the reaction above, the products give a
  • A Purple solution
  • B Purple precipitate
  • C Colourless precipitate
  • D Colourless solution
View Answer & Explanation