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 21: Electronic configuration of an elements 13x in the subsidiary energy level is Options:
  A) $1s^{2}2s^{2}2p^{6}3s^{2}3p^1$
  B) $1s^{2}2s^{2}2p^{4}3p^{1}3s^1$
  C) $1s^{2}2s^{2}2p^{6}3s^{2}3p^3$
  D) $1s^{1}2s^{2}2p^{6}3s^{2}3p^4$
  Show Answer
  The correct answer is A .
• Question 22: A correct electrochemical series can be obtained from K, Na, Ca, Al, Mg, Zn, Fe, Pb, H, Cu, Hg, Ag, Au by interchanging? Options:
  A) Al and Mg
  B) Zn and Fe
  C) Zn and Pb
  D) Pb and H
  E) Au and Hg
  Show Answer
  The correct answer is A .
• Question 23: The arrangement of particles in crystal lattices can be studied using Options:
  A) X - rays
  B) γ - rays
  C) α - rays
  D) β - rays
  Show Answer
  The correct answer is A .
• Question 24:

  (1/2)Zn²⁺_(aq) + e^- → (1/2) Zn_(s)

  In the reaction above, calculate the quantity of electricity required to discharge zinc.

  [F = 96 500 C mol^-1]

  Options:
  A) 0.965 * 10₄C
  B) 4.820 * 10₄C
  C) 9.650 * 10₄C
  D) 48.200 * 10₄C
  Show Answer
  The correct answer is C .
• Question 25: An oxidation state of or in K2CrO7 Options:
  A) 7
  B) 6
  C) 5
  D) 4
  Show Answer
  The correct answer is B .
• Question 26: What is the correct IUPAC name for NO₂^-? Options:
  A) Dioxonitrate (IV) ion
  B) Trioxonitrate (III) ion
  C) Trioxonitrate (IV) ion
  D) Dioxonitrate (II) ion
  Show Answer
  The correct answer is D .
• Question 27:

  CH₃COOH_(g) → H_4(g) + CO_2(g)

  The reaction above is

  Options:
  A) Carboxylation
  B) Decarboxylation
  C) Acidification
  D) Esterification
  Show Answer
  The correct answer is B .
• Question 28: wH₂SO₄ + xAI(OH)₃ → yH₂O + = zAI₂(SO₄)₃. The respective values of w.x.y and z in the equation above are? Options:
  A) 2,2,5 and 1
  B) 3,2,5 and 2
  C) 3,2,6 and 1
  D) 2,2,6 and 2
  Show Answer
  The correct answer is C .
• Question 29: If the difference in electronegativity of elements P and Q is 3.0. The bond that will be formed between them is Options:
  A) metallic
  B) covalent
  C) co-ordinate
  D) ionic
  Show Answer
  The correct answer is D .
• Question 30:

  Which of the following could not be alkane?

  Options:
  A) C${}_4$H${}_{10}$
  B) C${}_5$H${}_{12}$
  C) C${}_7$H${}_{14}$
  D) C${}_8$H${}_{18}$
  Show Answer
  The correct answer is C .