Search SchoolNGR

Saturday, 23 May 2026
Register . Login

Chemistry Past Questions and Answers

Jamb 1999 Chemistry Questions

Question 16:
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
Question 17:
The set of pollutants that is most likely to be produced when petrol is accidentally spilled on plastic materials and ignited is
  • A CO, CO<sup style='font-size: smaller;'>2</sup> and SO<sup style='font-size: smaller;'>2</sup>
  • B CO, HCL and SO<sup style='font-size: smaller;'>2</sup>
  • C CO, CO<sup style='font-size: smaller;'>2</sup> and HCL
  • D SO<sup style='font-size: smaller;'>2</sup>, CO<sup style='font-size: smaller;'>2</sup> and HCL
View Answer & Explanation
Question 18:
What is observed when aqueous solutions of each of tetraoxosulphate (VI) acid, potassium trioxoiodate (V) and potassium iodide are mixed together?
  • A A white precipitate is formed
  • B A green precipitate is formed
  • C The mixture remains colourless
  • D The mixture turns reddish brown
View Answer & Explanation
Question 19:
The solution with the lowest pH value is
  • A 5 ml of (m/10) HCL
  • B 10 ml of (m/10) HCL
  • C 15 ml of (m/5) HCL
  • D 20 ml of (m/8) HCL
View Answer & Explanation
Question 20:
The solubility product of Cu(IO3)2 is 1.08 * 10-7. Assuming that neither ions react appreciable with water to form H+ and OH-, what is the solubility of this salt?
  • A 2.7 * 10<sup style='font-size: smaller;'>-8</sup> mol dm<sup style='font-size: smaller;'>-3</sup>
  • B 9.0 * 10<sup style='font-size: smaller;'>-8</sup> mol dm<sup style='font-size: smaller;'>-3</sup>
  • C 3.0 * 10<sup style='font-size: smaller;'>-3</sup> mol dm<sup style='font-size: smaller;'>-3</sup>
  • D 9.0 * 10<sup style='font-size: smaller;'>-3</sup> mol dm<sup style='font-size: smaller;'>-3</sup>
View Answer & Explanation