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 171: An example of aromatic compound is? Options:
  A) C₆H₁₃OH
  B) C₆H₁₃CI
  C) C₆H₅OH
  D) C₆H₁₄
  Show Answer
  The correct answer is C .
• Question 172: Vulcanization involve the removal of Options:
  A) monometer
  B) the single bond
  C) the double bond
  D) a polymer
  Show Answer
  The correct answer is C .
• Question 173: Sodium chloride has no solubility product value because of its? Options:
  A) saline nature
  B) high solubility
  C) low solubility
  D) insolubility
  Show Answer
  The correct answer is B .
• Question 174:

  During the electrolysis of copper II sulphate between platinum electrodes, if litmus solution is added to the anode compartment

  Options:
  A) the litmus turns blue but no gas is evolved
  B) the litmus turns blue and oxygen is evolved
  C) the litmus turns blue and hydrogen is evolved
  D) the litmus turns red and oxygen is evolved
  Show Answer
  The correct answer is D .
• Question 175: If hydrogen sulphide gas is passed into a solution of a pure iron chloride, a yellow deposit appears. If the deposit is filtered, a pale green solution is left behind. The pale green solution is Options:
  A) dilute sulphuric acid
  B) dilute hydrochloric acid
  C) unreacted hydrogen sulphide in water
  D) iron (III) chloride
  E) Iron (II) chloride
  Show Answer
  The correct answer is E .
• Question 176: 2.5 g of a hydrate barium salt gave on heating, 2.13 g of the anhydrous salt. Given that the relative molecular mass of the of the anhydrous salt is 208, the number of molecules of water of crystallization of the barium salt is Options:
  A) 10
  B) 7
  C) 5
  D) 2
  E) 1
  Show Answer
  The correct answer is D .
• Question 177: Two metallic ions associated with hard water are Options:
  A) copper and zinc
  B) magnesium and silver
  C) calcium and magnesium
  D) potassium and tin
  E) sodium and lead
  Show Answer
  The correct answer is C .
• Question 178:

  

  The IUPAC nomenclature of the compound above is

  Options:
  A) 4 - ethyloctane
  B) 5 - ethyloctane
  C) 5 - propylheptane
  D) 3 - propylheptane
  Show Answer
  The correct answer is D .
• Question 179: The pollutant that contributes to the depletion of the ozone layer is Options:
  A) CFCs
  B) NO₂
  C) SO₂
  D) CO
  Show Answer
  The correct answer is A .
• Question 180:

  

  The tabulated results below were obtained by titration 10.0 cm³ of water with soup. The titration was repeated with the same sample of water after boiling. The ratio of permanent to temporary hardness is

  Options:
  A) 1.5
  B) 1.4
  C) 4.1
  D) 5.1
  Show Answer
  The correct answer is C .