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Saturday, 13 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 16:
Which of the following changes is physical?
  • A Adding iron filing to aerated water
  • B Adding sodium metal to water
  • C Cooling a solution of Iron (II) sulphate to obtain the hydrated salt
  • D Cooling water to obtain ice
  • E Burning the domestic gas (Utilgas) for cooking
View Answer & Explanation
Question 17:
By means of filtration, one component can be obtained pure from an aqueous mixture of sodium chloride and
  • A Potassium nitrate
  • B Sand
  • C Lead nitrate
  • D Sugar (glucose)
  • E Starch
View Answer & Explanation
Question 18:
A gas jar was inverted over burning yellow phosphorus floating over water in a beaker. After burning, the water level was found to rise in the gas jar. The water level rises because
  • A Pressure inside the gas jar is greater than pressure outside it
  • B The air in the gas jar had been used up by burning
  • C Oxygen in the gas jar had been used up by burning
  • D Nitrogen in the gas jar had been used up by burning
  • E The temperature in the jar had risen considerably
View Answer & Explanation
Question 19:
Which of the following substances would you see as an indicator in the titration of sodium carbonate solution against hydrochloric acid (complete neutralisation)?
  • A Litmus paper
  • B Phenolphthalein
  • C Methyl orange
  • D Universal indicator
  • E None of these
View Answer & Explanation
Question 20:
Which of the five atoms can be described by the following properties: Relative atomic mass is greater than 30 but less than 40, it has odd atomic number and forms a unipositive ion in solution?
  • A T
  • B W
  • C X
  • D Y
  • E Z
View Answer & Explanation