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 81: Which of the following substances is the most abundant in the universe? Options:
  A) Carbon
  B) Air
  C) Water
  D) Oxygen
  E) Hydrogen
  Show Answer
  The correct answer is E .
• Question 82: Which of the following elements will form oxide which will dissolve both in dilute HNO₃ and NaOH solutions to form salts? Options:
  A) Al
  B) Mg
  C) Ag
  D) Mn
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  The correct answer is A .
• Question 83: The property which makes alcohol soluble in water is the Options:
  A) boiling point
  B) hydrogen bonding
  C) ionic character
  D) covalent nature
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  The correct answer is B .
• Question 84:

  

  The IUPAC name of the compound above is
  Options:
  A) 2,2-dimethyl but -1-yne
  B) 2,2-dmethyl but -1-ene
  C) 3,3-dimethyl but -1-ene
  D) 3,3-dimethyl but-1-yne
  Show Answer
  The correct answer is C .
• Question 85: Oxyacetylene flame is used for iron-welding because it Options:
  A) Makes the iron metals solidify very quickly
  B) Combines with oxygen to give a pop sound
  C) Evolves a lot of heat when burnt
  D) Dissociates to produce carbon (IV) oxide and oxygen
  Show Answer
  The correct answer is C .
• Question 86:

  Consider the following exothermic reaction

  2SO_2(g) + O_2(g) ↔ 2SO_3(g)

  If the temperature of the reaction is reduced from 800°C to 500°C, an no other change takes place, then

  Options:
  A) the reaction rate increases
  B) concentration of SO₃ decreases
  C) concentration of SO₃ increases
  D) SO₂ gas becomes unreactive
  E) O₃ gas becomes unreactive
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  The correct answer is C .
• Question 87:

  Which of the following metals is commonly alloyed with copper to make brass?

  Options:
  A) Iron
  B) Nickel
  C) Aluminum
  D) Zinc
  Show Answer
  The correct answer is D .
• Question 88: 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 concentrated tetroxosulphate (VI) acid
  D) bubbled through sodium hydroxide
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  The correct answer is D .
• Question 89: Chromatography is used to separate components of mixtures which differ in their rates of? Options:
  A) diffusion
  B) migration
  C) reaction
  D) sedimentaion
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  The correct answer is B .
• Question 90: 0.25 mole of hydrogen chloride was dissolved in distilled water and the volume made up of 0.50 dm³. If 15.0 cm³ of the solution requires 12.50 cm³ of aqueous sodium trioxocarbonate (IV) for neutralization, calculate the concentration of the alkaline solution Options:
  A) 0.30 mol dm³
  B) 0.40 mol dm³
  C) 0.50 mol dm³
  D) 0.60 mol dm³
  Show Answer
  The correct answer is A .