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Sunday, 14 June 2026
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Chemistry Past Questions and Answers

Jamb 1981 Chemistry Questions

Question 36:
5cm3 of a saturated solution of sodium chloride at 30°C gave, on careful evaporation, 1.95g of solid salt. The solubility of sodium chloride at 30°C?
(Na = 23, Cl = 35.5)
  • A 5.00 mole dm<sup style='font-size: smaller;'>3</sup>
  • B 5.67 mole dm<sup style='font-size: smaller;'>3</sup>
  • C 6.00 mole dm<sup style='font-size: smaller;'>3</sup>
  • D 6.67 mole dm<sup style='font-size: smaller;'>3</sup>
  • E 7.00 mole dm<sup style='font-size: smaller;'>3</sup>
View Answer & Explanation
Question 37:
In the extraction of iron, which of the following reactions does NOT take place in the blast furnace?
  • A CO<sub style='font-size: smaller;'>2</sub> + C → 2CO
  • B 2Fe<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>3</sub> + 3C → 4Fe + 3CO<sub style='font-size: smaller;'>2</sub>
  • C Fe<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>3</sub> + 3C → 2Fe + 3CO<sub style='font-size: smaller;'>2</sub>
  • D CaCO<sub style='font-size: smaller;'>3</sub> → CaO + CO<sub style='font-size: smaller;'>2</sub>
  • E CaO + SiO<sub style='font-size: smaller;'>2</sub> → CaSiO<sub style='font-size: smaller;'>3</sub>
View Answer & Explanation
Question 38:
Pure sulphuric acid is a liquid of 1:84 density. What volume of it would be required to prepare 250 cm3 of 2.0 M solution?
(H = 1, S = 32, O = 16)
  • A 2.00
  • B 2.66
  • C 3.00
  • D 3.66
  • E 4.00
View Answer & Explanation
Question 39:
What mass of sodium carbonate solution is in 500 cm3 of 0.1 molar sodium carbonate solution?
(Na = 23, C = 12, O = 16)
  • A 10.6 g
  • B 5.3 g
  • C 500 g
  • D 10 g
  • E 20 g
View Answer & Explanation
Question 40:
Which of the following compounds and elements would sublime on exposure to the atmosphere?
  • A Ice
  • B Sulphur
  • C Phosphurous
  • D Iodine
  • E Potassium iodie
View Answer & Explanation