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 411: The number of isomers formed by C₆H₁₄ is Options:
  A) 4
  B) 5
  C) 2
  D) 3
  Show Answer
  The correct answer is B .
• Question 412: Sodium carbonate crystals on exposure to a dry atmosphere change to a white powder. This phenomenon is known as? Options:
  A) deliquescence
  B) hygroscopy
  C) oxidation
  D) efforescence
  E) sublimation
  Show Answer
  The correct answer is D .
• Question 413: An increase in the pressure exerted on gas at a constant temperature results in Options:
  A) a decrease in the number of effective collisions
  B) a decrease in volume
  C) an increase in the average intermolecular distance
  D) an increase in volume
  Show Answer
  The correct answer is B .
• Question 414:

  What is the product of the electrolysis of aqueous sodium chloride (NaCl) using inert electrodes?

  Options:
  A) Hydrogen gas at the cathode and chlorine gas at the anode
  B) Hydrogen gas at the cathode and oxygen gas at the anode
  C) Sodium metal at the cathode and chlorine gas at the anode
  D) Sodium metal at the cathode and oxygen gas at the anode
  Show Answer
  The correct answer is A .
• Question 415: Which of the following equations represents an oxidizing action of sulphur dioxide? Options:
  A) SO₂ + 2HNO₂ → H₂SO₄ + 2NO₂ + heat
  B) 2SO₂ + 2H₂O + O₂ → 2H₂SO₄
  C) SO₂ + 2H₂O + CI₂ → H₂SO₄ + 2HCI
  D) SO₂ + 2H₂S → 3S + 2H₂O
  E) K₂Cr₂O₇ + H₂SO₄ + 3SO₂ → K₂SO₄ + Cr₂(SO₄)₃ + H₂O
  Show Answer
  The correct answer is D .
• Question 416:

  Which of the following types of alkanols undergo oxidation to produce alkanoic acids.I. Primary alkanols

  II. Secondary alkanols

  III. Tertiary alkanols

  Options:
  A) I, II and III
  B) I and II only
  C) III only
  D) I only
  Show Answer
  The correct answer is D .
• Question 417: A basic postulate of the kinetic theory of gases is that the molecules of a gas move in straight lines between collisions. This implies that? Options:
  A) collisions are perfectly elastic
  B) forces of repulsion exist
  C) forces of repulsion are in equilibrium
  D) collision are inelastic
  Show Answer
  The correct answer is A .
• Question 418:

  Benzene can be converted to its derivative toluene by the addition of a methyl group. The reaction is an example of

  Options:
  A) Nucleophilic substitution
  B) Elimination reaction
  C) Electrophilic substitution
  D) Addition reaction
  Show Answer
  The correct answer is C .
• Question 419:

  The mass of one Avogadro number of helium atoms is?

  Options:
  A) 1.00gram
  B) 4.00gram
  C) 8.00gram
  D) 6.00gram
  Show Answer
  The correct answer is B .
• Question 420:

  

  The compound above exhibits

  Options:
  A) Geometric isomerism
  B) Positional isomerism
  C) Structural isomerism
  D) Optical isomerism
  Show Answer
  The correct answer is D .