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 341: The gas that can be dried using concentrated tetraoxosulphate (VI) acid is Options:
  A) hydrogen bromide
  B) Sulphur (IV) oxide
  C) hydrogen sulphide
  D) ammonia
  Show Answer
  The correct answer is B .
• Question 342: Three liquids X, Y and Z containing only hydrogen and carbon were burnt on a spoon. X and Y burnt with sooty flames while Z did not. Y is able to discharge the colour of bromine water whereas X and Z cannot. Which of the liquids would be aromatic in nature? Options:
  A) X and Z
  B) Y
  C) X
  D) Z
  Show Answer
  The correct answer is B .
• Question 343:

  Zn _(s) + CuSO ₄(aq) → ZnSO ₄(aq) + Cu _(s)

  In the reaction above, the oxidation number of the reducing agent changes from

  Options:
  A) 0 to + 4
  B) 0 to + 2
  C) + 1 to + 2
  D) + 1 to + 3
  Show Answer
  The correct answer is B .
• Question 344: Which of the noble gases has the greatest ionization energy Options:
  A) He
  B) Xe
  C) Ar
  D) Rr
  Show Answer
  The correct answer is A .
• Question 345: The compound that is used as an anaesthetic is Options:
  A) CCl₄
  B) CH Cl₃
  C) CH₂Cl₂
  D) CH₃Cl
  Show Answer
  The correct answer is B .
• Question 346:

  Which of the following compounds is an example of an electrovalent bond?

  Options:
  A) NaCl (sodium chloride)
  B) CO2 (carbon dioxide)
  C) H2O (water)
  D) CH4 (methane)
  Show Answer
  The correct answer is A .
• Question 347:

  What is the maximum number of electrons that can occupy the second energy level (n=2)?

  Options:
  A) 2 electrons
  B) 18 electrons
  C) 8 electrons
  D) 32 electrons
  Show Answer
  The correct answer is C .
• Question 348:

  What is the chemical formula of rust, which is formed on the surface of iron in the presence of oxygen and moisture?

  Options:
  A) Fe${}_3$O${}_4$
  B) FeO
  C) Fe(OH)3
  D) Fe${}_2$O${}_3$
  Show Answer
  The correct answer is D .
• Question 349: Which of the following oxides of nitrogen is unstable in air? Options:
  A) NO₂
  B) NO
  C) N₂O₄
  D) N₂O_5-
  Show Answer
  The correct answer is B .
• Question 350: Which of the following is a solvent for perfumes? Options:
  A) C₅H₁₂
  B) C₄H₆
  C) CH₃COOH
  D) C₂H₅OH
  Show Answer
  The correct answer is D .