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Monday, 15 June 2026
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Chemistry Past Questions and Answers

Topic: Separation of mixtures and purification of chemical substances

Jamb Chemistry Questions - Separation of mixtures and purification of chemical substances

Question 46:
Which of the following statements about phosphorus is NOT correct?
  • A Phosphorus is a solid mineral
  • B Phosphorus is obtained by oxidation reaction of phosphate
  • C Phosphorus exists in two allotropic forms
  • D Both forms of phosphorus are interconvertible
  • E Yellow phosporus ignites when rubbed on a rough surface
View Answer & Explanation
Question 47:
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 48:
An efflorescent compound is a substance that?
  • A Absorbs water froom the air without dissolving in it
  • B Is capable of giving off coloured luminosity
  • C Gives out water to the atmosphere
  • D Absorbs water from the air and dissolves in it
  • E Gives out its water of crystallization on heating
View Answer & Explanation
Question 49:
The IUPAC name for
  • A 1-methlpentane
  • B 3-methylbutane
  • C 2-methylbutane
  • D 1-dimethylpropane
  • E 2-methylpentane
View Answer & Explanation
Question 50:
Cotton is almost pure?
  • A Starch
  • B Protein
  • C Animal fibre
  • D Celluose
  • E Mineral fibre
View Answer & Explanation