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:

  In the electrolysis of dilute sulphuric acid using platinum electrodes, the products obtained at the anode and cathode are:

  Anode Cathode

  Options:
  A) Sulphur hydrogen
  B) Hydrogen oxygen
  C) Oxygen Hydrogen
  D) Hydrogen sulphate ions
  E) Sulphur oxygen
  Show Answer
  The correct answer is C .
• Question 2: In which of the following are water molecules in the most disorderly arrangement? Options:
  A) Ice at -10°C
  B) Ice at 0°C
  C) Water at 100°C
  D) Steam at 100°C
  Show Answer
  The correct answer is D .
• Question 3:

  Sodium sulphate decahydrate (Na₂SO₄.10 H₂O) on exposure to air loses all its water of crystallization.

  The process of loss is known as

  Options:
  A) efflorescence
  B) hygroscopy
  C) deliquescence
  D) effervescence
  E) dehydration
  Show Answer
  The correct answer is A .
• Question 4: The nitrogen obtained from air has a density higher than the one from nitrogen-containing compounds because the one from air is contaminated with Options:
  A) water vapour
  B) oxgyen
  C) rare gases
  D) carbon (IV) oxide
  Show Answer
  The correct answer is C .
• Question 5: Ethene reacts with hydrogen bromide to give Options:
  A) CH₂Br₂
  B) CH₃CH₂Br
  C) C₂H₂Br₂
  D) CHBr₂
  Show Answer
  The correct answer is B .
• Question 6: In the laboratory preparation of trioxonitrate (V) acid the nitrogen(iv) oxide formed as a by-product is removed by Options:
  A) further heating
  B) adding concentrated H₂SO₄
  C) cooling the acid solution with cold water
  D) bubbling air through the acid solution
  Show Answer
  The correct answer is D .
• Question 7:

  The nucleusof a hydrogen atom consist of a?

  Options:
  A) 1 proton only
  B) 1 proton, 2 neutron
  C) 1 neutron only
  D) 1 electron only
  Show Answer
  The correct answer is A .
• Question 8:

  

  Choose the correct answer from the options above.

  When Fehling's solution is added to two isomeric carbonyl compounds X and Y with the molecular formula C ₅H ₁₀O, compound X gives a red precipitate while Y does not react. It can be inferred that X is

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

  CH_4(g) + Cl_2(g) → CH₃ Cl_(s) + HCl_(g)

  The major factor that influence the rate of the reaction above is

  Options:
  A) catalyst
  B) temperature
  C) concentration
  D) light
  Show Answer
  The correct answer is D .
• Question 10:

  2H${}_2$ + O${}_2$ 2H${}_2$O

  From the equationabove, calculate the volume of unreacted oxygen gas if a mixture of 50cm${}^3$ of hydroden and 75cm${}^3$ of oxygen are involved

  Options:
  A) 85cm${}^3$
  B) 50cm${}^3$
  C) 125cm${}^3$
  D) 55cm${}^3$
  Show Answer
  The correct answer is B .