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 1751: The intermediate product formed when ethanol is progressively oxidized to ethanoic acid with potassium heptaoxodichromate (IV) is Options:
  A) butanal
  B) ethanal
  C) methanal
  D) propanal
  Show Answer
  The correct answer is B .
• Question 1752: According to Charle's law, the volume of a gas becomes zero at Options:
  A) −100°c
  B) −273°c
  C) −373°c
  D) 0°c
  Show Answer
  The correct answer is B .
• Question 1753:

  Equal volumes of CO,SO₂, and H₂S were released into a room at the same point and time. Which of the following gives the order of diffusion of the gases to the opposite corner of the room?

  (S = 32, C = 12, O = 16, N = 14, H = 1)

  Options:
  A) CO, SO₂,NO₂,H₂S
  B) SO₂,NO₂,H₂S,CO
  C) CO,H₂S,SO₂,NO₂
  D) CO,H₂S,NO₂,SO₂
  Show Answer
  The correct answer is D .
• Question 1754: The major source of oxides of nitrogen is from the burning of Options:
  A) coal
  B) wood
  C) fuel
  D) chlrofluorocarbons
  Show Answer
  The correct answer is C .
• Question 1755:

  The radio isotope used in industrial radiography for the rapid checking of faults in welds and casting is?

  Options:
  A) carbon-14
  B) phosphorus-32
  C) cobalt
  D) iodine-131
  Show Answer
  The correct answer is C .
• Question 1756: A few drops of NaOH solution was added to an unknown salt forming a white precipitate which is insoluble in excess solution. The cation likely present is Options:
  A) Zn²⁺
  B) Pb²⁺
  C) Ca²⁺
  D) Al³⁺
  Show Answer
  The correct answer is C .
• Question 1757:

  What mass of Cu would be produced by the cathodic reduction of Cu${}^{2+}$  when 1.60A of current passes through a solution of CuSO${}_4$ for 1 hour. (F=96500Cmol${}^{-1}$ , Cu=64)

  Options:
  A) 7.64g
  B) 3.82g
  C) 1.91g
  D) 0.96g
  Show Answer
  The correct answer is C .
• Question 1758: The dispersion of a liquid in a liquid medium will give Options:
  A) an emulsion
  B) a fog
  C) a gel
  D) an aerosol
  Show Answer
  The correct answer is A .
• Question 1759:

  An element X has two isotopes, ²⁰₁₀X and ²⁰₁₀X, present in the ratio 1:3. The relative atomic mass of X would be?

  Options:
  A) 20.5
  B) 21.0
  C) 21.5
  D) 22.0
  E) 22.5
  Show Answer
  The correct answer is C .
• Question 1760:

  The same current is passed for the same time through solutions of AgNO₃ and CuSO₄ connected in series. How much silver will be deposited if 1.0 g of copper is produced?

  [Cu = 63.5, S = 32, O = 16, Ag = 108, N = 14]

  Options:
  A) 1.7 g
  B) 3.4 g
  C) 6. 8 g
  D) 13. 6 g
  Show Answer
  The correct answer is B .