Chemistry Exam Past Questions and Answers | JAMB, WAEC and NECO

Chemistry is the study of the substances that make up matter. It looks at their properties, how they react with each other, and how these reactions can create new substances.

• Question 1: Which of the following is a deliquescent compound? Options:
  A) Na₂CO₃
  B) CaCl₂
  C) CuO
  D) Na₂CO₃.10H₂O
  Show Answer
  The correct answer is B .
• Question 2: The mass of an atom is determined by Options:
  A) its ionization potential
  B) its electrochemical potential
  C) the number of protons and electrons
  D) the number of neutrons and protons
  E) the number of neutrons and electrons
  Show Answer
  The correct answer is D .
• Question 3: The function of sulphur during vulcanization rubber is to? Options:
  A) act as catalyst for the polymerization of rubber molecules
  B) convert rubber from thermosetting to thermo plastics polymer
  C) from chains which bind rubber molecules together
  D) break down rubber polyer
  E) shorten the chain length of rubber polyer
  Show Answer
  The correct answer is C .
• Question 4: The drying agent suitable for drying ammonia is Options:
  A) Calcium Chloride
  B) Calcium Oxide
  C) Phosphorus(V) Oxide
  D) Concentrated H₂SO₄
  Show Answer
  The correct answer is B .
• Question 5: The product formed when propanol is heated over a copper catalyst in the absence of oxygen are Options:
  A) CH₃CH₂CHO and H₂
  B) CH₃CHO and CO₂
  C) CH₃CH₂COOH and H₂
  D) CH₃COOH and CO₂
  Show Answer
  The correct answer is D .
• Question 6: A few drops of concentrated PCI are added to about 10cm³ of a solution of pH 3.4. The pH of the resulting mixtures is? Options:
  A) less than 3.4
  B) greater than 3.4
  C) unaltered
  D) the same as that of pure water
  Show Answer
  The correct answer is C .
• Question 7: Deliquescent substance are used for Options:
  A) Cooling
  B) Wetting
  C) Melting
  D) Drying
  Show Answer
  The correct answer is D .
• Question 8: A certain liquid has a high boiling point. It is viscous, non-toxic, miscible with water being very hygroscopic. This liquid is most likely to be? Options:
  A) CH₃CH₂CH₂HO
  B) CH₃CHOHCH₃
  C) CH₃CH₂CHOHCH₃
  D) CH₂OHCHOHCH₂OH
  Show Answer
  The correct answer is D .
• Question 9: Which of the following will produce a solution with pH less than 7 at equivalent point? Options:
  A) HNO ₃ +NaOH
  B) H ₂SO ₄ + KOH
  C) HC +Mg (OH) ₂
  D) HNO ₃ + KOH
  Show Answer
  The correct answer is C .
• Question 10:

  The heat of formation of ethene, C${}_2$H${}_4$ is 50 kJmol${}^{-1}$, and that of ethane, C${}_2$H${}_6$ is -82kJmol${}^{-1}$. Calculate the heat evolved in the process:

  C${}_2$H${}_4$ + H${}_2$ $\to$ C${}_2$H${}_6$

  Options:
  A) -122kJ
  B) -132kJ
  C) -88kJ
  D) -60kJ
  Show Answer
  The correct answer is B .