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 421:

  Which of the following reactions is an oxidation process?

  Options:
  A) 2H${}^{+}$ + 2e${}^{-}$ $\to$ H${}_2$
  B) 2O${}^{2-}$ + 4e${}^{-}$ $\to$ O${}_2$
  C) OCl${}^{-}$ + H${}_2$O + 2e${}^{-}$ $\to$ 2OH${}^{-}$ + Cl${}^{-}$
  D) Cl + e${}^{-}$ $\to$ Cl${}^{-}$
  Show Answer
  The correct answer is B .
• Question 422:

  

  The IUPAC nomenclature of the compound above is

  Options:
  A) 4 - ethyloctane
  B) 5 - ethyloctane
  C) 5 - propylheptane
  D) 3 - propylheptane
  Show Answer
  The correct answer is D .
• Question 423: A mixture of sugar and sulphur can be separated by Options:
  A) dissolution in water, evapouration and filtration
  B) filtration, evaporation and dissolution in water
  C) dissolution in water, filtration and evaporation
  D) evaporation, dissolution in water and filtration
  Show Answer
  The correct answer is C .
• Question 424: Which of the following properties is not peculiar to matter? Options:
  A) Kinetic energy of particles increases from solid to gas
  B) Random motion of particles increases from gas to solid
  C) Orderliness of particles increases from gas to liquid
  D) Random motion of particles increases from liquid to gas
  Show Answer
  The correct answer is B .
• Question 425:

  MnO^-4_(aq) + Y + 5Fe²⁺_(aq) → Mn²⁺_(aq) + 5Fe²⁺_(aq) + 4H₂O_(l)
  In the equation above, Y is

  Options:
  A) 5H⁺_(aq)
  B) 4H⁺_(aq)
  C) 10H⁺_(aq)
  D) 8H⁺_(aq)
  Show Answer
  The correct answer is D .
• Question 426: Which of the following is NOT a true statement of the kinetic Theory of Gases? Options:
  A) The molecules move at random
  B) The size of molecules is negligble as compared with the volume of gas
  C) The molecular collisions are perfectly elastic
  D) Every molecule has the same kinetic energy at a particular temperature
  E) The average kinetic energy is proportional to the absolute temperature of the gas
  Show Answer
  The correct answer is D .
• Question 427: The dissolution of common salt in water is a physical change because Options:
  A) the salt can be obtained by crystallization
  B) the salt can be recovered by the evaporation of water
  C) heat is not generated during mixing
  D) the solution will not boil at 100^oC
  Show Answer
  The correct answer is C .
• Question 428:

  When a substance is oxidized, it

  Options:
  A) Loses electrons
  B) Gains oxygen atoms
  C) Gains electrons
  D) Loses protons (H+ ions)
  Show Answer
  The correct answer is A .
• Question 429: Aromatic and aliphatic hydrocarbons can be distinguished from each other by the? Options:
  A) action of bromine
  B) use of polymerization reaction
  C) action of heat
  D) use of oxidation reaction
  Show Answer
  The correct answer is C .
• Question 430: Some properties of chemical substances are mentioned below... i. sour taste ii. slippery touch iii. yields alkaline gas with ammonium salt iv. has pH less than 7 v. turns phenolphthalein pink.Which of the above are NOT typical properties of alkalis? Options:
  A) i, iv and v
  B) iv and v
  C) i and iv
  D) ii and v
  E) ii, iii and iv
  Show Answer
  The correct answer is C .