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Friday, 14 August 2026
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Chemistry Past Questions and Answers

Topic: Separation processes

Jamb Chemistry Questions - Separation processes

Question 11:
Crude petroleum pollutant usually seen on some Nigerian creeks and waterways can be dispersed or removed by
  • A Heating the affected parts in order to boil off the petroleum
  • B Mechanically stirring to dissolve the petroleum in water
  • C Pouring organic solvents to dissolve the petroleum
  • D Spraying the water with stergents
  • E Cooling to freeze out the petroleum
View Answer & Explanation
Question 12:
Which of the following separation processes is most likely to yield high quality ethanol (>95%) from palm wine?
  • A Fractional distillation without a dehydrant
  • B Simple distillation with a dehydrant
  • C Fractional distillation with a dehydrant
  • D Column chromatography
  • E Evaporation
View Answer & Explanation
Question 13:
Solid sodium hydroxide on exposure to air absorbs a gas and ultimately gives another alkaline substance with the molecular formula?
  • A NaOH.H<sub style='font-size: smaller;'>2</sub>O
  • B NaOH.N<sub style='font-size: smaller;'>2</sub>
  • C Na<sub style='font-size: smaller;'>2</sub>CO<sub style='font-size: smaller;'>3</sub>O
  • D NaHCO<sub style='font-size: smaller;'>3</sub>
  • E NaNO<sub style='font-size: smaller;'>3</sub>O
View Answer & Explanation
Question 14:
0.499g 0f CuSO4.xH2O when heated to constant weight gave a residue of 0.346g. the value of x is? (Cu = 63.5, S = 32.0, O = 16, H = 1)
  • A 0.5
  • B 2.0
  • C 3.0
  • D 4.0
  • E 5.0
View Answer & Explanation
Question 15:
In the experiment, which of the following observations would suggest that a solid sample is a mixture? The
  • A Solid can be ground to a fine powder
  • B Density of the solid is 2.25gdm<sup style='font-size: smaller;'>-3</sup>
  • C Solid begins to melt at 573k but is not completely melted until 648k
  • D Solid absorbs moisture from the atmosphere and turns into liquid
  • E Solid melts at 300k
View Answer & Explanation