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Friday, 06 November 2026
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Chemistry Past Questions and Answers

Jamb 1982 Chemistry Questions

Question 21:
When a little brine was added to a metal nitrate a white precipitate was formed which first turned violet and then black on exposure to ai. The metal nitrate is therefore?
  • A Sodium nitrate
  • B Mercuric nitrate
  • C Lithium nitrate
  • D Silver nitrate
  • E Potassium nitrate
View Answer & Explanation
Question 22:
If atom X with six electrons in its outermost shell combines with atom Y with one electron in its outermost shell to form an ionic compound, then?
  • A Six atoms of X will combine with one of Y
  • B Two atoms of X will combine with six of Y
  • C One atom of X will combine with two of Y
  • D Two atoms of X will combine with one of Y
  • E One atom of X will combine with six of Y
View Answer & Explanation
Question 23:
The nitrogen gas obtained by burning an excess of phosphorus in air has a density higher than the nitrogen from nitrogen compounds because the nitrogen from air is contaminated with?
  • A Some unburnt phosporus
  • B P<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>5</sub> vapour
  • C Some oxygen
  • D Rare gases
  • E Carbondioxide
View Answer & Explanation
Question 24:
When air is passed through alkaline pyrogallol and then over quicklime, the only gases left are?
  • A Nitrogen and carbondoxide
  • B The rare gases
  • C Nitrogen and oxygen
  • D Nitrogen and the rare gases
  • E Nitrogen, carbonioxide and the rare gases
View Answer & Explanation
Question 25:
9.8g of solid potassium chlorate (KCIO3) were added to 40 cm3 of water and heated to dissolve all the solid. As he solution cooled, crystals of potassium chlorate started forming at 60°C. The solubility of potassium chlorate at 66°C is therefore?
  • A 24.5 mole per dm<sup style='font-size: smaller;'>3</sup>
  • B 0.2 mole per dm<sup style='font-size: smaller;'>3</sup>
  • C 10.0 mole per dm<sup style='font-size: smaller;'>3</sup>
  • D 20.0 mole per dm<sup style='font-size: smaller;'>3</sup>
  • E 2.0 mole per dm<sup style='font-size: smaller;'>3</sup>
View Answer & Explanation