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 1511: Hardening of an oil may achieved by? Options:
  A) boiling the oil with water
  B) boiling the oil with a catalyst
  C) treating the oil with sodium hydroxide
  D) treating the oil with hydrogen and catalyst
  E) distilling oil under reduced pressure
  Show Answer
  The correct answer is D .
• Question 1512: Tetraoxosulphate (IV) ions are finally tested using? Options:
  A) acidified silver nitrate
  B) acidified barium chloride
  C) ime-water
  D) dilute hydrochloric acid
  E) acidified lead nitrate
  Show Answer
  The correct answer is B .
• Question 1513: When a piece of charcoal enclosed in a cylinder containing air is ignited Options:
  A) the toatl volume of air is increased
  B) the relative amount of oxygen present is increased
  C) the relative amount of nitrogen present is decreased
  D) the relative amount of carbondioxide present is increased
  E) the ratio of oxygen to nitrogen in the system is increased
  Show Answer
  The correct answer is D .
• Question 1514: Which of the following separation processes is most likely to yield high quality ethanol (>95%) from palm wine? Options:
  A) Fractional distillation without a dehydrant
  B) simple distillation with a dehydrant
  C) fractional distillation with a dehydrant
  D) column chromatography
  E) evaporation
  Show Answer
  The correct answer is C .
• Question 1515: Which of these represents a redox reaction? Options:
  A) AgNO₃ + NaCl → AgCAl + NaNO₃
  B) H₂S + Pb(NO₃) → PbS + 2HNO₃
  C) CaCO₃ → CaO + CO₂
  D) Zn + 2HCl → ZnCl₂ + H₂
  Show Answer
  The correct answer is D .
• Question 1516:

  Na${}_2$CO${}_3$ + 2HCl $\to$ 2NaCl + H${}_2$O + CO${}_2$

  The indicator most suitable for this reaction should have a pH equal to

  Options:
  A) 5
  B) 7
  C) 3
  D) 9
  Show Answer
  The correct answer is C .
• Question 1517:

  Which of the following does not support the fact that air is a mixture?

  Options:
  A) the constituents of air are in a fixed proportion by mass
  B) it cannot be represented with a chemical formula
  C) the constituents of air can be separated by physical by physical means
  D) none of the above
  Show Answer
  The correct answer is A .
• Question 1518: 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 1519:

  

  The two functional groups in the above compound are

  Options:
  A) alcohol and amine
  B) acid and amine
  C) aldehyde and acid
  D) ketone and amine
  Show Answer
  The correct answer is B .
• Question 1520: An isomer of C₅H₁₂ is Options:
  A) 2–ethyl butane
  B) butane
  C) 2–methyl butane
  D) 2–methyl propane
  Show Answer
  The correct answer is C .