Search SchoolNGR

Thursday, 18 June 2026
Register . Login

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 216:
The pair of organic compounds that are isomers is
  • A Benzene and methylbenzene
  • B Trichloromethane and tetrachloromethane
  • C Ethanol and propane
  • D But-1-ene and but-2-ene
View Answer & Explanation
Question 217:
A little quantity of trichloromethane (b.pt 60,oC) was added to a large quantity of ethanol (b.pt 78,oC). The most probable boiling point of the resultant mixture is from
  • A 69 <sup style='font-size: smaller;'>o</sup>C - 70 <sup style='font-size: smaller;'>o</sup>C
  • B 70 <sup style='font-size: smaller;'>o</sup>C – 74 <sup style='font-size: smaller;'>o</sup>C
  • C 82 <sup style='font-size: smaller;'>o</sup>C – 84 <sup style='font-size: smaller;'>o</sup>C
  • D 60 <sup style='font-size: smaller;'>o</sup>C – 78 <sup style='font-size: smaller;'>o</sup>C
View Answer & Explanation
Question 218:
The chromatography separation of ink is based on the ability of the components to
  • A React with solvent
  • B React with each other
  • C Dissolve in each other in the column
  • D Move at different speeds in the column
View Answer & Explanation
Question 219:
The solubility of a salt of molar mass 101g at 20oC is 0.34 mol dm-3. If 3.40g of the salt is dissolved completely in 250cm3 of water in a beaker, the resulting solution is
  • A A suspension
  • B Saturated
  • C Unsaturated
  • D Supersaturated
View Answer & Explanation
Question 220:
25cm3 of a 0.2 mol dm3 solution of Na2CO3 requires 20 cm3 of a solution of HCl for neutralization. The concentration of the HCl solution is
  • A 0.5 mol dm<sup style='font-size: smaller;'>3</sup>
  • B 0.6 mol dm<sup style='font-size: smaller;'>3</sup>
  • C 0.2 mol dm<sup style='font-size: smaller;'>3</sup>
  • D 0.4 mol dm<sup style='font-size: smaller;'>3</sup>
View Answer & Explanation