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 1781:

  MnO₂ + 2CI^- + 4H⁺ → MnO²⁺ + CI₂ + 2H₂O.

  The changes is oxidation numbers when the manganese, chloride and hydrogen ions react according to the above equation are respectively?

  Options:
  A) 2, 2, 4
  B) -1, -2, 4
  C) -2, 1, 0
  D) 2, 4, 0
  Show Answer
  The correct answer is C .
• Question 1782:

  

  Use the diagram above to answer this question.

  Which of the following structural formula is NOT isomeric with the others?

  Options:
  A) A
  B) B
  C) C
  D) D
  E) E
  Show Answer
  The correct answer is D .
• Question 1783:

  To obtain pure carbon(ii)oxide from its mixture with carbon(iv)oxide, the mixture should be?

  Options:
  A) Passed over heated copper(ii)oxide
  B) Bubbled through water
  C) Bubbled through conc H${}_2$SO${}_4$
  D) Bubbled through conc NAOH
  Show Answer
  The correct answer is D .
• Question 1784: Which of the following types of bonding does not involve the formation of new substances? Options:
  A) Metallic
  B) covalent
  C) co-ordinate
  D) electrovalent
  Show Answer
  The correct answer is A .
• Question 1785: Temporary hard water is formed when rain water containing dissolved carbon(IV) oxide flows over deposits of Options:
  A) CaCO₃
  B) Na₂CO₃
  C) Na₂SO₄
  D) CaSO₄
  Show Answer
  The correct answer is A .
• Question 1786: In which of the following reactions does hydrogen peroxide act as a reducing agent? Options:
  A) H₂S + H₂O₂ $\to$ S + 2H₂O
  B) PbSO₃ + H₂O₂ $\to$ PbSO₄ + H₂O
  C) 2I+ 2H⁺ + H₂O₂ $\to$ I₂ + 2H₂O
  D) PbO₂ + 2HNO₃ + H₂O₂ $\to$ Pb(NO₃)₂ + 2H₂O + O₂
  E) SO₂ + H₂O₂ $\to$ H₂SO₄
  Show Answer
  The correct answer is D .
• Question 1787: Which of the following compounds is NOT formed by the action of chlorine on methane? Options:
  A) CH₃CI
  B) C₂H₅CI
  C) CH₂CI₂
  D) CHCI₃
  Show Answer
  The correct answer is B .
• Question 1788: The equilibrium of an endothermic reaction which proceeds with an increase in volume can be shifted in the reverse direction by Options:
  A) increasing the temperature and decreasing the pressure
  B) increasing the pressure and increasing the temperature
  C) decreasing the temperature and increasing the pressure
  D) decreasing the pressure and decreasing the temperature
  Show Answer
  The correct answer is C .
• Question 1789:

  

  Which of the following compounds is a secondary alkanol?

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is A .
• Question 1790:

  A dense white fume is formed when ammonia gas reacts with

  Options:
  A) O_2(g)
  B) H_2(g)
  C) Cl_2(g)
  D) HCl_(g)
  Show Answer
  The correct answer is D .