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Friday, 12 June 2026
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Chemistry Past Questions and Answers

Jamb 2019 Chemistry Questions

Question 126:
Methane is prepared in the laboratory by heating a mixture of sodium ethanoate with soda lime. The chemical constituent(s) of soda lime is/are
  • A Ca(OH)\(_2\) and NaOH
  • B Na\(_2\)CO\(_3\)
  • C NaCl
  • D NaOH
View Answer & Explanation
Question 127:
Which of the following sets of operation will completely separate a mixture of sodium chloride, sand and iodine?
  • A Addition of water, filtration, evaporation to dryness and sublimation
  • B Filtration, evaporation to dryness, addition of water and sublimation
  • C Sublimation, filtration, evaporation and addition of water
  • D Sublimation, addition of water, filtration and evaporation to dryness
View Answer & Explanation
Question 128:
200cm\(^3\) of 0.50mol/dm\(^3\) solution of calcium hydrogen trioxocarbonate (IV) is heated. The maximum weight of solid precipitated is
  • A 10g
  • B 25g
  • C 20g
  • D 15g
View Answer & Explanation
Question 129:
Which of the following conditions will most enhance the spontaneity of a reaction?
  • A \(\Delta\)H is negative and greater than T\(\Delta\)S
  • B \(\Delta\)H is negative and \(\Delta\)S = 0
  • C \(\Delta\)H is positive and less than T\(\Delta\)S
  • D \(\Delta\)H is positive and equal to T\(\Delta\)S
View Answer & Explanation
Question 130:
X is a substance which liberates CO\(_2\) on treatment with concentrated H\(_2\)SO\(_4\). A warm solution of X can decolorize acidified KMnO\(_4\). X is
  • A HCOOH
  • B NaHCO\(_3\)
  • C FeCO\(_3\)
  • D H\(_2\)C\(_2\)O\(_4\)
View Answer & Explanation