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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 21:
Consider the solubility curves of three salts X, Y and Z given in the diagram. If each solution of the salt contains 200 g, and is heated to 100oC, which solution or solutions will deposit 100 g of the solute when suddenly cooled to 0oC?
  • A X only
  • B Y only
  • C Z only
  • D X and Z
  • E Y and Z
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Question 22:
Which are the correct IUPAC names for H-CO\(_2\)CH\(_3\) and CH \(\equiv\) CH
  • A Methyl methanoate and ethene
  • B Metanoic acid and ethyne
  • C Ethyl methanoate and ethyne
  • D Methyl methanoate and ethyne
  • E Ethanoic acid and ethene
View Answer & Explanation
Question 23:
Which of the following substances are all made by the process of polymerization?
  • A Nylon and soap
  • B Ethanoic acid margarine and ethanol
  • C Nylon and artificial rubber
  • D Soap and butane
  • E Margarine and nylon
View Answer & Explanation
Question 24:
Helium atoms are chemically unreactive because
  • A There are no electrons around the nucleus
  • B The number of protons equals the number of electrons
  • C There are equal number of protons and neutrons in the nucleus
  • D The outer electron shell is completely filled
  • E The atoms contain only protons
View Answer & Explanation
Question 25:
An anhydride is
  • A A compound wich has no water of crystallization
  • B An oxide whose solution in water has a PH greater than 7
  • C An oxide whose solution in water has a PH less than 7
  • D An oxide that has hydrogen atoms
  • E An amphoteric oxide
View Answer & Explanation