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 101: The reaction Mg + H₂O → MgO + H₂ takes place only in the presence of? Options:
  A) excess Mg ribbon
  B) excess cold water
  C) very hot water
  D) steam
  Show Answer
  The correct answer is D .
• Question 102:

  When ammonia and hydrogen ion bond together to form ammonium ion, the bond formed is called

  Options:
  A) electrovalent bond
  B) co-ordinate bond
  C) ionic bond
  D) covalent bond
  Show Answer
  The correct answer is B .
• Question 103: The basicity of CH₃COOH is Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is A .
• Question 104: Chlorine gas turns damp starch-iodide paper Options:
  A) pink
  B) colourless
  C) red
  D) dark blue
  Show Answer
  The correct answer is D .
• Question 105: The electronic configuration of Mg ²⁺ is Options:
  A) ls ²2s ²2P ⁶3s²3P²
  B) Is²2s²2P⁶
  C) ls²2s²2p⁶3s²
  D) ls²2s²2P⁴
  Show Answer
  The correct answer is B .
• Question 106:

  

  50 cm³ of sulphur (lV) oxide, 800 cm³ of carbon (IV) oxide will respectively saturate 1.0cm³ of water at 15^oC. Which of the following is suitable for demonstrating the fountain experiment?

  Options:
  A) Sulphur (IV) oxide and hydrogen chloride.
  B) Carbon (IV) oxide and ammonia
  C) Ammonia and hydrogen chloride
  D) Carbon (IV) oxide and Sulphur (IV) oxide
  Show Answer
  The correct answer is C .
• Question 107: A metallic ion X²⁺ with an inert gas structure contains 18 electrons. How many protons are there in this ion? Options:
  A) 20
  B) 18
  C) 16
  D) 2
  Show Answer
  The correct answer is A .
• Question 108:

  Which type of chemical combination involves the transfer of electrons from one atom to another, resulting in the formation of oppositely charged ions?

  Options:
  A) Ionic bonding
  B) Hydrogen bonding
  C) Covalent bonding
  D) Metallic bonding
  Show Answer
  The correct answer is A .
• Question 109: Which of the following is NOT a redox reaction? Options:
  A) 2HNO₂ + 2HI → 2H₂O + 2NO + I₂
  B) Zn + H₂SO₄ → ZnSO₄ + H₂
  C) Ca(HCO₃)₂ → CaCO₃ + H₂O + CO₂
  D) 4FeO + O₂ → 2Fe₂O₃
  E) 2Na + Cl₂ → 2NaCl
  Show Answer
  The correct answer is C .
• Question 110: Tartaric acid is used industrially to Options:
  A) make baking powder
  B) make fruit juices
  C) remove rust
  D) dry substance
  Show Answer
  The correct answer is A .