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 1411: A gas that will turn orange potassium heptaoxodichromate (lV) solution to clear green is? Options:
  A) sulphur (ii) oxide
  B) hydrogen sulphide
  C) sulphide (lV) oxide
  D) hydrogen chloride
  Show Answer
  The correct answer is A .
• Question 1412: Which of the following compounds is a neutral oxide? Options:
  A) Carbon (IV) oxide
  B) Sulphur (Vl) oixide
  C) Sulphur (IV) oxide
  D) Carbon (ll) oxide
  Show Answer
  The correct answer is D .
• Question 1413: In the extraction of iron in the blast furnace, limestone is used to? Options:
  A) release CO₂ for the reaction
  B) reduce the iron ore
  C) increase the strenght of the iron
  D) remove impurities
  Show Answer
  The correct answer is D .
• Question 1414:

  

  The curve depicts titration between

  Options:
  A) Strong acid and strong base
  B) Strong acid and weak base
  C) Weak acid and weak base
  D) Weak acid and strong base
  Show Answer
  The correct answer is C .
• Question 1415:

  What mass of water is produced when 8.0g of hydrogen reacts with excess oxygen?

  Options:
  A) 8.0g
  B) 16.0g
  C) 36.0g
  D) 72.0g
  Show Answer
  The correct answer is D .
• Question 1416:

  

  Which of the curves in the above graph illustrates the behaviour of an ideal gas?

  Options:
  A) W
  B) X
  C) Y
  D) Z
  Show Answer
  The correct answer is C .
• Question 1417:

  Mg_(s) + 2HCl_(aq) → MgCl_2(aq) + H_2(g)

  From the equation above, the mass of magnesium required to react with 250cm³ of 0.5M HCl is

  [Mg = 24]

  Options:
  A) 0.3g
  B) 1.5g
  C) 2.4g
  D) 3.0g
  Show Answer
  The correct answer is B .
• Question 1418: Two elements, P and Q with atomic numbers 11 and 8 respectively , combine chemically to form the compound P_xQ_Y. The respective values of x and y are? Options:
  A) 1 and 1
  B) 1 and 2
  C) 2 and 1
  D) 3 and 1
  Show Answer
  The correct answer is C .
• Question 1419: In which of the following processes is iron being oxidized?1 Fe + H₂SO₄ → FeSO₄ +H₂2 FeSO₄ + H₂S → FeS + H₂SO₄3 2FeCI₂ + Cl₂ → 2FeCl₃4 2FeCl₃ + SnCl₂ + → 2FeCl₂ + SnCl₄ Options:
  A) 1 only
  B) 2 only
  C) 3 only
  D) 1 and 3
  E) 2 and 4
  Show Answer
  The correct answer is D .
• Question 1420:

  How many grams of hydrogen gas will be liberated when 6g of magnesium ribbon dissolves in 500cm³ of 6M HCl?
  (Mg = 24, H = 1, Cl = 35.5)

  Options:
  A) 1.2 g
  B) 0.7 g
  C) 0.5 g
  D) 0.3 g
  E) 0.12 g
  Show Answer
  The correct answer is C .