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 2011: In the laboratory preparation of oxygen, dried oxygen is usually collected over Options:
  A) hydrochloric acid
  B) mercury
  C) calcium chloride
  D) tetraoxosulphate (VI) acid
  Show Answer
  The correct answer is B .
• Question 2012:

  The number of grammes of potassium hydroxide in 250cm³ of one molar solution is?

  (K = 39, O = 16, H = 1)

  Options:
  A) 40g
  B) 52g
  C) 100g
  D) 26g
  E) 14g
  Show Answer
  The correct answer is E .
• Question 2013: Cotton is almost pure? Options:
  A) starch
  B) protein
  C) animal fibre
  D) celluose
  E) mineral fibre
  Show Answer
  The correct answer is D .
• Question 2014: Water can be obtained as the only product during Options:
  A) combustion of hydrocarbons
  B) neutralization of an acid by base
  C) combustion of hydrogen
  D) electrolysis of brine
  E) boiling water
  Show Answer
  The correct answer is C .
• Question 2015:

  

  The I.U.P.A.C name for the compound is

  Options:
  A) isopropylethene
  B) acetylene
  C) 3- methylbutane
  D) 2-methylbutane
  E) 5-methylpentane
  Show Answer
  The correct answer is D .
• Question 2016:

  What mass of Cu would be produced by the cathodic reduction of Cu${}^{2+}$  when 1.60A of current passes through a solution of CuSO${}_4$ for 1 hour. (F=96500Cmol${}^{-1}$ , Cu=64)

  Options:
  A) 7.64g
  B) 3.82g
  C) 1.91g
  D) 0.96g
  Show Answer
  The correct answer is C .
• Question 2017:

  How many valence electrons are contained in the element ${}_{15}^{31}P$?

  Options:
  A) 3
  B) 4
  C) 15
  D) 31
  Show Answer
  The correct answer is A .
• Question 2018:

  How many pi ($\pi$) bonds are there in an alkene with six carbon atoms?

  Options:
  A) 4
  B) 6
  C) 5
  D) 3
  Show Answer
  The correct answer is D .
• Question 2019:

  5SO_2(g) + 2KMnO_4(aq) + 2H₂O_(l) → K₂SO₄ + 2MnSO_4(aq) + 2H₂SO_4(aq)

  In the reaction above, the products give a

  Options:
  A) purple solution
  B) purple precipitate
  C) colourless precipitate
  D) colourless solution
  Show Answer
  The correct answer is D .
• Question 2020: An experiment produces a gaseous mixtures of carbon (IV) oxide and carbon (II) oxide. In order to obtain pure carbon (II) oxide, the gas mixture should be? Options:
  A) passed over heated copper (II) oxide
  B) bubbled through concentrated tetraoxosulphate (IV) acid
  C) bubbled through sodium hydroxide solution
  D) bubbled through water
  Show Answer
  The correct answer is C .