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Saturday, 03 October 2026
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Chemistry Past Questions and Answers

Jamb 1999 Chemistry Questions

Question 11:
The method that can be used to convert hard water to soft water is
  • A Chlorination
  • B Passage over activated charcoal
  • C The use of an ion-exchange resin
  • D Aeration
View Answer & Explanation
Question 12:
1s2, 2s2, 2p6, 3s2, 3p6, 3d7, 4s2
An element with the electronic configuration above is a
  • A Non-metal
  • B Metal
  • C Transition element
  • D Group two element
View Answer & Explanation
Question 13:
Given that electronegativity increases across a period and decreases down a group in the periodic table, in which of the following compounds will the molecules be held together by the strongest hydrogen bond?
  • A HF<sub style='font-size: smaller;'>(g)</sub>
  • B NH<sub style='font-size: smaller;'>3(g)</sub>
  • C CH<sub style='font-size: smaller;'>4(g)</sub>
  • D HCl<sub style='font-size: smaller;'>(g)</sub>
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Question 14:
0.25 mole of hydrogen chloride was dissolved in distilled water and the volume made up of 0.50 dm3. If 15.0 cm3 of the solution requires 12.50 cm3 of aqueous sodium trioxocarbonate (IV) for neutralization, calculate the concentration of the alkaline solution
  • A 0.30 mol dm<sup style='font-size: smaller;'>3</sup>
  • B 0.40 mol dm<sup style='font-size: smaller;'>3</sup>
  • C 0.50 mol dm<sup style='font-size: smaller;'>3</sup>
  • D 0.60 mol dm<sup style='font-size: smaller;'>3</sup>
View Answer & Explanation
Question 15:
The correct order of increasing oxidation number of the transition metal ions for the compounds K2Cr2O7, V2O5 and KMnO4 is
  • A V<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>5</sub> < K<sub style='font-size: smaller;'>2</sub>Cr<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>7</sub> < KMnO<sub style='font-size: smaller;'>4</sub>
  • B K<sub style='font-size: smaller;'>2</sub>Cr<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>7</sub> < KMnO<sub style='font-size: smaller;'>4</sub> < V<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>5</sub>
  • C KMnO<sub style='font-size: smaller;'>4</sub> < K<sub style='font-size: smaller;'>2</sub>Cr<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>7</sub> < V<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>5</sub>
  • D KMnO<sub style='font-size: smaller;'>4</sub> < V<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>5</sub> < K<sub style='font-size: smaller;'>2</sub>Cr<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>7</sub>
View Answer & Explanation