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 21:

  What technique is suitable for separating a binary solution of potassium chloride and potassium trioxochlorate (V)?

  Options:
  A) Fractional crystallization
  B) Fractional distillation
  C) Filtration
  D) Evaporation
  Show Answer
  The correct answer is A .
• Question 22: The number of hydroxonium ions produced by one molecule of an acid in aqueous solution is its Options:
  A) basicity
  B) acid strength
  C) pH
  D) concentration
  Show Answer
  The correct answer is B .
• Question 23: In the preparation of ammonia, which of the following is used as the drying agent? Options:
  A) CaO
  B) CaCI₂
  C) Conc. H₂SO₄
  D) P₂O₅
  E) H₃PO₄
  Show Answer
  The correct answer is A .
• Question 24:

  

  The compound above is the product of the oxidation of

  Options:
  A) 2-methlbutan-2-ol
  B) 2-methylbutan -1- ol
  C) 2, 3-dimethylprop 1-ol
  D) Pentan -2- ol
  Show Answer
  The correct answer is B .
• Question 25:

  2-methylprop-1-ene is an isomer of

  Options:
  A) 3-methyl but-1-ene
  B) 2-methyl but-1-ene
  C) but-2-ene
  D) pent-2-ene
  Show Answer
  The correct answer is C .
• Question 26: Indicate which of the following statements is not true as we move from left to right along the periodic Table: Options:
  A) atomic number of elements increases
  B) atomic mass of elements increases
  C) electropositive character of elements increases
  D) electronegative character of elements increases
  E) number of electrons in the outermost orbits of element increases
  Show Answer
  The correct answer is C .
• Question 27:

  What is the chemical structure of soap and detergent molecules?

  Options:
  A) Hydrophilic head and hydrophobic tail
  B) Hydrophilic head and hydrophilic tail
  C) Hydrophobic head and hydrophobic tail
  D) Hydrophilic tail and hydrophobic head
  Show Answer
  The correct answer is A .
• Question 28: A given mass of gas occupies 2 dm³ at 300k. At what temperature will its volume be doubled keeping the pressure constant? Options:
  A) 400k
  B) 480k
  C) 550k
  D) 600k
  Show Answer
  The correct answer is D .
• Question 29:

  A gaseous metallic chloride MCl_x consists of 20.22% of M by mass. The formula of the chloride is

  [M = 27, Cl = 35.5]

  Options:
  A) MCl
  B) MCl₂
  C) MCl₃
  D) M₂Cl₆
  Show Answer
  The correct answer is C .
• Question 30: Which of the following contains two amphoteric oxides? Options:
  A) sodium oxide, Zinc oxide , Magnesium oxide
  B) Aluminium oxide, Calcium oxide, Zinc oxide
  C) Potassium oxide, Lithium oxide, Carbon monoxide
  D) Silver oxide, Lead oxide, Sodium oxide
  E) Sulphur dioxide, Aluminium oxide, Carbon monoxide
  Show Answer
  The correct answer is B .