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Wednesday, 20 May 2026
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Chemistry Past Questions and Answers

Jamb 1988 Chemistry Questions

Question 16:
When H2S gas is passed into a solution of iron (III) chloride, the colour changes from yellow to green. This is because?
  • A H<sub style='font-size: smaller;'>(s)</sub>S is reduced to S
  • B Fe<sup style='font-size: smaller;'>3+</sup> ions are oxidized by H<sub style='font-size: smaller;'>(s)</sub>S
  • C Fe<sup style='font-size: smaller;'>3+</sup> ions are oxidized Fe<sup style='font-size: smaller;'>3+</sup> ions
  • D Fe<sup style='font-size: smaller;'>3+</sup> ions are reduced to Fe<sup style='font-size: smaller;'>2+</sup> ions
View Answer & Explanation
Question 17:
Suitable reagents for the laboratory preparation nitrogen are?
  • A Sodium dioxonitrate (III) and ammonium chloride
  • B Sodium dioxonitrate (V) and ammonium chloride
  • C Sodium chloride and ammonium chloride
  • D Sodium chloride and ammonium diozonitrate (III)
View Answer & Explanation
Question 18:
The thermal decomposition of copper (ll)trioxonitrate (V) yields copper (ll) oxide, oxygen and?
  • A Nitrogen (ll) oxide
  • B Nitrogen (l) oxide
  • C Nitrogen (lV) oxide
  • D Nitrogen
View Answer & Explanation
Question 19:
Chlorine is produced commmercially by?
  • A Electrolysis of dilute hydrochloric acid
  • B Electrolysis of brine
  • C Neutralization of hydrogen chloride
  • D Heating potassium trioxochlorate (V)
View Answer & Explanation
Question 20:
Aluminium is extracted commercially from its ore by?
  • A Heating aluminium oxide with coke in a furance
  • B The electrolysis of fused aluminium oxide in cryolite
  • C Treating cryolite with sodium hydroxide solution under prressure
  • D Heating sodium aluminium silicate to a high temperature
View Answer & Explanation