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 metals cannot replace hydrogen from water or steam? Options:
  A) Sodium
  B) Magnesium
  C) Iron
  D) Calcium
  E) Copper
  Show Answer
  The correct answer is E .
• Question 2: Iron is often galvanized in order to Options:
  A) Make it more malleable
  B) Remove the impurities unit
  C) Protect it against corrosion
  D) Render it passive
  Show Answer
  The correct answer is C .
• Question 3:

  What is the common name for ethanoic acid?

  Options:
  A) Acetic acid
  B) Butyric acid
  C) Propionic acid
  D) Formic acid
  Show Answer
  The correct answer is A .
• Question 4: How many lone pairs of electron are there on the central atom of the H₂O molecules? Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is B .
• Question 5: Ammonia gas is normally dried with? Options:
  A) concentrated sulphuric acid
  B) quicklime
  C) anhydrous calcium chloride
  D) magnesium sulphate
  Show Answer
  The correct answer is B .
• Question 6: The energy value of petrol can be determined by a Options:
  A) bomb calorimeter
  B) catalytic cracker
  C) fractionating column
  D) thermometer
  Show Answer
  The correct answer is C .
• Question 7: Which of the following are the products of the reaction between CH₃COOH and CI₂ in sunlight? Options:
  A) CICH₂COOH + HCI
  B) CH₃COCI + HOCI
  C) CH₃COOCI + HCI
  D) CH₃COCI + HO₂
  Show Answer
  The correct answer is A .
• Question 8: Weighed salts Y and Z were left exposed in the laboratory overnight. In the morning Y had gained weight, and Z had become liquid. What conclusion could be drawn about the nature of the two salts? Options:
  A) Z is efflorescent
  B) Y and Z are efflorescent
  C) Y and Z are deliquescent
  D) Y and Z are hygroscopic
  E) Y is deliquescent
  Show Answer
  The correct answer is C .
• Question 9:

  

  In the diagram above, which of the curves represents the evolution of oxygen with time in the equation 2KClO_3(s) → 2KCl_(s) + 3O_2(g)?

  Options:
  A) X
  B) Y
  C) Z
  D) R
  Show Answer
  The correct answer is C .
• Question 10: The molar ratio of oxygen to nitrogen in dissolved air is 2:1 whereas the ratio is 4:1 in atmospheric air because? Options:
  A) nitrogen is less soluble than oxygen
  B) oxygen is heavier than nitrogen
  C) nitrogen has a higher partial pressure in air
  D) gases are hydrated in water
  Show Answer
  The correct answer is A .