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: Which of the following gases may not be dried with concentrated sulphuric acid? Options:
  A) HCl
  B) N₂
  C) Cl₂
  D) SO₂
  E) NH₃
  Show Answer
  The correct answer is E .
• Question 2: The volume occupies by 1.58g of a gas at s.t.p is 500cm³. What is the relative molecular mass of the gas? (G.M.V at s.t.p = 22.40dm³) Options:
  A) 28
  B) 32
  C) 44
  D) 71
  Show Answer
  The correct answer is D .
• Question 3: Alkanoates are formed by the reaction of alkanoic acid with? Options:
  A) Alkyl halides
  B) alkanols
  C) ethers
  D) sodium
  Show Answer
  The correct answer is B .
• Question 4: In a flame test for calcium, the flame appears Options:
  A) green when viewed through a blue glass
  B) blue when viewed through a blue glass
  C) orange -red when viewed through a blue glass
  D) brick-red when viewed through a blue-glass
  Show Answer
  The correct answer is D .
• Question 5: Na₂C₂O₄ + CaCl₂ → CaC₂O₄ + 2NaCl. Given a solution of 1.9g of sodium oxalate in 50g of water at room temperature, calculate the minimum volume of 0.1 M calcium oxalate using the above equation? Options:
  A) 1.40 χ 10² dm³
  B) 14.0 χ 10² cm³
  C) 1.40 χ 10^-2 dm^-2
  D) 14.0 χ 10^-2 cm³
  Show Answer
  The correct answer is A .
• Question 6: Two organic compounds K and L were treated with a few drops of Fehling's solutions respectively . K formed a brick-red precipitate while L, remains unaffected. The compound K is an Options:
  A) alkanol
  B) alkane
  C) alkanal
  D) alkanone
  Show Answer
  The correct answer is C .
• Question 7:

  The part of the total energy of a system that accounts for the useful work done in a system is known as

  Options:
  A) Enthalpy change
  B) None of the above
  C) Gibb's free energy
  D) Entropy
  Show Answer
  The correct answer is C .
• Question 8: The salt formed from a weak acid and a strong base hydrolyzes in water to form Options:
  A) A saturated solution
  B) an acidic solution
  C) a buffer solution
  D) an alkaline solution
  Show Answer
  The correct answer is D .
• Question 9:

  3H${}_{2(g)}$+ N2 ⇔ 2NH${}_{3(g)}$ ; H= -ve

  In the reaction above, lowering of temperature will

  Options:
  A) have no effect on the equilibrium position
  B) increase the rate of both the forward and reverse reactions equally
  C) favour the forward reaction
  D) favour the reverse reaction
  Show Answer
  The correct answer is C .
• Question 10: An aqueous solution of an inorganic salt gave white precipitate (i) soluble in excess aqueous NaOH (ii) insoluble in excess aqueous NH₃ (iii) with dilute HCl. The cation present in the inorganic salt is? Options:
  A) Na₄⁺
  B) Ca⁺⁺
  C) Zn⁺⁺
  D) Al⁺⁺⁺
  E) Pb₊₊
  Show Answer
  The correct answer is E .