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 1: Sodium and potassium belong to the same group of the Periodic Table. This is because? Options:
  A) both are metals
  B) both are soft and lighter than water
  C) both form cations by losing electrons
  D) both have identical electronic configuration
  E) both react with water vigorously
  Show Answer
  The correct answer is D .
• Question 2:

  Zn_(s) + CuSO_4(aq) $\to$ ZnSO_4(aq) + Cu_(s)

  In the reaction above, the oxidizing agent is

  Options:
  A) CuSO_4(aq)
  B) ZnSO_4(aq)
  C) Cu_(s)
  D) Zn_(s)
  Show Answer
  The correct answer is A .
• Question 3: An example of a secondary amine is? Options:
  A) propylene
  B) di-butylamine
  C) methylamine
  D) trimethylamine
  Show Answer
  The correct answer is B .
• Question 4: The chromatography separation of ink is based on the ability of the components to Options:
  A) React with solvent
  B) React with each other
  C) Dissolve in each other in the column
  D) Move at different speeds in the column
  Show Answer
  The correct answer is D .
• Question 5:

  A chemical process in which there is a gain of electrons is known as?

  Options:
  A) Sublimation
  B) Reduction
  C) Oxidation
  D) Distillation
  Show Answer
  The correct answer is B .
• Question 6: A mixture of petrol and water can be separated through Options:
  A) centrifugation
  B) distillation
  C) the use of separating funnel
  D) the use of filter paper
  Show Answer
  The correct answer is C .
• Question 7:

  

  In the diagram above, the curve that represents the production of oxgyen gas from the decomposition of KCIO₃ in the presence of MnO₂ catalyst is

  Options:
  A) R
  B) P
  C) S
  D) Q
  Show Answer
  The correct answer is B .
• Question 8: The line observed in the sample hydrogen spectrum are due to emission of? Options:
  A) electrons from the atoms
  B) energy by proton transition
  C) energy by electron transition
  D) neutron from the atom
  Show Answer
  The correct answer is C .
• Question 9: Which of the following equilibria is unaffected by a pressure change? Options:
  A) 2NaCI(s) ↔ 2Na _(I) + CI_2(g)
  B) H _2(g) + I_2(g) ↔ 2HI_(g)
  C) 2O_3(g) ↔ 3O_2(g)
  D) 2NO_2(g) ↔ N₂O_4(g)
  Show Answer
  The correct answer is B .
• Question 10: A mixture of starch solution and potassium iodide was placed in a test tube. On adding dilute tetraoxosulphate (lV) acid and then K₂Cr₂O₇ solutions, a blue-black colour was produced. In this reaction, the? Options:
  A) iodide is oxidized
  B) tetraoxosulphate (Vl) acid acts as an oxidizing agent
  C) starch has been oxidized
  D) K₂Cr₂O₇ is oxidized
  Show Answer
  The correct answer is C .