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: 10.0 dm³ of water was added to 2.0 mol dm^-3 of 2.5dm³ solution of HCl. What is the concentration of the final solution in mol dm^-3? Options:
  A) 0.4
  B) 8.0
  C) 2.0
  D) 0.5
  Show Answer
  The correct answer is A .
• Question 2: Cu₂S_(s) + O2(g) = 2CU_(s) + SO2_2(g) Options:
  A) +1 to 0
  B) 0 to +2
  C) +2 to +1
  D) 0 to +1
  Show Answer
  The correct answer is A .
• Question 3: The gas that can be collected by downward displacement of air is Options:
  A) chlorine
  B) sulphur (IV) oxide
  C) carbon (IV) oxide
  D) ammonia
  Show Answer
  The correct answer is D .
• Question 4: The process that occurs when two equivalent forms of a compound are in equilibrium is Options:
  A) Isotopy
  B) Resonance
  C) Isomerism
  D) Reforming
  Show Answer
  The correct answer is B .
• Question 5:

  A concentrated solution containing H⁺, Cu²⁺, OH^- and Cl^- was electrolyzed using platinum electrodes.

  The ion that will be discharged at the cathode is

  Options:
  A) Cu²⁺
  B) Cl^-
  C) H⁺
  D) OH^-
  Show Answer
  The correct answer is A .
• Question 6: When a bottle of Coca-Cola is opened, bubbles of evolve. The gas is? Options:
  A) hydrogen
  B) carbon monoxide
  C) carbon dioxide
  D) sulphur oxide
  E) chlorine
  Show Answer
  The correct answer is C .
• Question 7: 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 8:

  On the basis of the electrochemical series, which of these ions will show the greater tendency to be discharged at the cathode in an electrolytic cell

  Options:
  A) cu${}^{2+}$
  B) sn${}^{2+}$
  C) fe${}^{2+}$
  D) zn${}^{2+}$
  Show Answer
  The correct answer is A .
• Question 9: The three-dimensional shape of methane is Options:
  A) hexagonal
  B) trigonal
  C) linear
  D) tetrahedral
  E) cubical
  Show Answer
  The correct answer is D .
• Question 10:

  Which of the following statements is true for strong electrolytes?

  Options:
  A) They do not conduct electricity in the molten state
  B) They completely dissociate into ions in solution
  C) They are non-polar substances
  D) They partially dissociate into ions in solution
  Show Answer
  The correct answer is B .