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 131: Which of the following processes takes place during electrolysis? Options:
  A) Positive ions are discharged at the anode bby gaining sufficient electrons to become neutral
  B) Negative ions are dicharged at the anode by gaining suficient electrons to become neutral
  C) Positive ions are discharged at the anode by losing sufficient electrons to become neutral
  D) Negative ions are discharge at the anode by losing sufficient electrons to become neutral
  E) Nothing happens
  Show Answer
  The correct answer is D .
• Question 132:

  A metal M displaces zinc from ZnCl, solution, solution

  This shows that

  Options:
  A) electrons flow from zinc to M
  B) M is more electropositive than zinc
  C) M is more electonegative than zinc
  D) zinc is more electropositive than M
  Show Answer
  The correct answer is B .
• Question 133: The process of converting linear alkanes to branched chain and cyclic hydrocarbons by heating in the presence of a catalyst to improve the quality of petrol is referred to as Options:
  A) refining
  B) craching
  C) reforming
  D) blending
  Show Answer
  The correct answer is C .
• Question 134: The petroleum fraction that is used in heating furnaces in industries is Options:
  A) diesel oil
  B) gasoline
  C) kerosene
  D) lubricating oil
  Show Answer
  The correct answer is A .
• Question 135:

  The shape of ammonia molecule is?

  Options:
  A) Trigonal planar
  B) Octahedral
  C) Square planar
  D) Tetrahedral
  Show Answer
  The correct answer is A .
• Question 136:

  A sample of a substance containing only C and H burns in excess O₂ to yield 4.4g of CO₂

  And 2.7 g of H₂O. The empirical formula of a substance is?(C = 12, O = 16, H = 1)

  Options:
  A) CH₃
  B) CH₂
  C) CH₄
  D) C₂H₂₄
  Show Answer
  The correct answer is A .
• Question 137: The ability of carbon to form long chains is referred to as Options:
  A) alkylation
  B) acylation
  C) catenation
  D) carbonation
  Show Answer
  The correct answer is C .
• Question 138: The process of converting starch to ethanol is Options:
  A) cracking
  B) distillation
  C) fermentation
  D) oxidation
  Show Answer
  The correct answer is C .
• Question 139: what is the pH of 0.00lmoldm³ solution of sodium hydroxide Options:
  A) 14
  B) 13
  C) 12
  D) 11
  Show Answer
  The correct answer is D .
• Question 140:

  The scientist who stated that matter can be converted into energy is?

  Options:
  A) Boyle
  B) Lavoiser
  C) Avogadro
  D) Einstein
  Show Answer
  The correct answer is D .