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 111: The type of iron that is best suited for welding, making nails, chains and iron rods is Options:
  A) pig iron
  B) wrought iron
  C) cast iron
  D) iron pyrites
  Show Answer
  The correct answer is B .
• Question 112:

  

  In the diagram, the function of the concentrated H₂SO₄ is to

  Options:
  A) purify the gas
  B) dry the gas
  C) liquefty the gas
  D) remove odour
  Show Answer
  The correct answer is B .
• Question 113: When ethanol is heated with excess concentrated sulphuric acid, the ethanol is? Options:
  A) oxidized to ethene
  B) polymerized to polyethene
  C) dehydrated to ethene
  D) dehydrated to ethyne
  Show Answer
  The correct answer is C .
• Question 114: Which of the following metals does NOT form a stable trioxocarbonate (IV)? Options:
  A) Fe
  B) Al
  C) Zn
  D) Pb
  E) none of the options is correct
  Show Answer
  The correct answer is E .
• Question 115: Pure solvents are obtained by Options:
  A) Distillation
  B) Condensation
  C) Extraction
  D) Evaporation
  Show Answer
  The correct answer is A .
• Question 116: The gas that can best be collected by downward displacement of air is Options:
  A) Chlorine
  B) Sulphur (IV) oxide
  C) Ammonia
  D) Carbon (IV) oxide
  Show Answer
  The correct answer is C .
• Question 117: Certain useful waxes are composed mainly of Options:
  A) amino acids
  B) glycerols
  C) alkanols
  D) alkanoates
  Show Answer
  The correct answer is B .
• Question 118:

  

  The solubility curves of four substances are shown in the figure above. Which of the four substances would crystallize from a saturated solution cooled from 353K(80^oC)to 323K(50C)?

  Options:
  A) P and Q
  B) P and R
  C) P and S
  D) R and S
  E) Q and R
  Show Answer
  The correct answer is D .
• Question 119: The oxidation state of manganese in potassium permanganate is Options:
  A) +7
  B) +5
  C) +3
  D) +2
  E) +1
  Show Answer
  The correct answer is A .
• Question 120:

  The reaction $2H_{2}S+S{O}_2\to 3S+2H_{2}O$ is

  Options:
  A) not a redox reaction because there is no oxidant in the reaction
  B) not a redox reaction because there is no reductant in the reaction
  C) a redox reaction in which H${}_2$S is the oxidant and SO${}_2$ is the reductant
  D) a redox reaction in which SO${}_2$ is the oxidant and H${}_2$S is the reductant
  Show Answer
  The correct answer is D .