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 2001: Which of the following is used as an 'anti-knock' in automobile engines? Options:
  A) Tetramethyl silane
  B) Lead tetra-ethyl
  C) Glycerol
  D) n-heptane
  Show Answer
  The correct answer is B .
• Question 2002:

  The reaction $2H_{2}S+S{O}_2\to 3S+2H_{2}O$ is

  Options:
  A) not a redox reaction because there is no oxidant in the reaction
  B) not a redox reaction because there is no reductant in the reaction
  C) a redox reaction in which H${}_2$S is the oxidant and SO${}_2$ is the reductant
  D) a redox reaction in which SO${}_2$ is the oxidant and H${}_2$S is the reductant
  Show Answer
  The correct answer is D .
• Question 2003: The mathematical expression of PH is Options:
  A) log ₁₀[OH^-]
  B) log ₁₀1/[H ₃ O⁺]
  C) log ₁₀[H ₃ O⁺]
  D) log ₁₀1/[OH ^-]
  Show Answer
  The correct answer is B .
• Question 2004:

  A blue litmus paper turns red when dipped into a solution. What does this indicate about the solution?

  Options:
  A) The solution is basic
  B) The solution is neutral
  C) The solution is acidic
  D) The litmus paper is faulty
  Show Answer
  The correct answer is C .
• Question 2005: In the laboratory preparation of chlorine from concentrated hydrochloric acid in the presence of potassuim tetraoxomanganate(VII) the produced is dried by passing it through Options:
  A) Concentrated tetraoxosulphate (VI) acid
  B) Anhydrous calcium chloride
  C) Calcium oxide
  D) Sodium hydroxide
  Show Answer
  The correct answer is A .
• Question 2006:

  What current will deposit 3.25g of zinc in 2hrs?

  [Zn = 65, F = 96500 mol^-]

  Options:
  A) 3.25A
  B) 2.00A
  C) 1.34A
  D) 0.67A
  Show Answer
  The correct answer is C .
• Question 2007: An oxidation state of or in K2CrO7 Options:
  A) 7
  B) 6
  C) 5
  D) 4
  Show Answer
  The correct answer is B .
• Question 2008: The combustion of ethene, C ₂H ₄, is given by the equation C ₂H ₄ + 30 ₂ → 2CO₂ + 2H₂ O; ∆H = - 1428 KJ. If the molar heats of formation of water and carbon (IV) oxide are - 286 kJ and - 396 kJ respectively, calculate the molar heat of formation of ethene in KJ Options:
  A) - 2792
  B) + 2792
  C) - 64
  D) + 64
  Show Answer
  The correct answer is D .
• Question 2009: Which of the following compounds will burn with a brick-red colour in a non-luminous Bunsen flame? Options:
  A) LiCI
  B) NaCl
  C) CaCl₂
  D) MgCl₂
  Show Answer
  The correct answer is C .
• Question 2010:

  Hydrocarbons which will react with Tollen's reagent conform to the general formula

  Options:
  A) C${}_n$H${}_{2n}$
  B) C${}_n$H${}_{2n+2}$
  C) C${}_n$H${}_{2n-2}$
  D) C${}_n$H${}_{2n+1}$OH
  Show Answer
  The correct answer is C .