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 101: 0.05 mol dm^-3 HCl is neutralized by 25 cm³ NaOH. If the volume of acid used is 32.00cm³, what is the concentration of the base Options:
  A) 0.016 mol dm^-3
  B) 0.032 mol dm^-3
  C) 0.039 mol dm^-3
  D) 0.064 mol dm^-3
  Show Answer
  The correct answer is D .
• Question 102:

  Potassium trioxochlorate (V)has a solubility of 1.5 mol dm ^-3 at 45 ^oC.On cooling this solution to a temperature of 20 ^oC, the solubility was found to be 0.5 mol dm ^-3. What mass of KCIO ₃ was crystalized out?

  [K = 39, Cl = 35.5 O =16].

  Options:
  A) 1.00g
  B) 10.00g
  C) 12.25g
  D) 122.50g
  Show Answer
  The correct answer is D .
• Question 103: A solution of calcium bromide contains 20 g dm ³ What is the molarity of the solution with respect to calcium bromide and bromide ions? [Ca = 40, Br = 80] Options:
  A) 0. 1, 0 . 1
  B) 0. 1, 0. 2
  C) 0. 1, 0. 05
  D) 0.05, 0.1
  Show Answer
  The correct answer is C .
• Question 104: An example of a neutral oxide is Options:
  A) AL₂O₃
  B) NO₂
  C) CO₂
  D) CO
  E) SO₂
  Show Answer
  The correct answer is D .
• Question 105: Methane is member of the homologous series called? Options:
  A) alkenes
  B) alcohols
  C) esters
  D) alkanes
  E) alkynes
  Show Answer
  The correct answer is D .
• Question 106: If atom X with six electrons in its outermost shell combines with atom Y with one electron in its outermost shell to form an ionic compound, then? Options:
  A) six atoms of X will combine with one of Y
  B) two atoms of X will combine with six of Y
  C) one atom of X will combine with two of Y
  D) two atoms of X will combine with one of Y
  E) one atom of X will combine with six of Y
  Show Answer
  The correct answer is C .
• Question 107: A few drops of concentrated PCI are added to about 10cm³ of a solution of pH 3.4. The pH of the resulting mixtures is? Options:
  A) less than 3.4
  B) greater than 3.4
  C) unaltered
  D) the same as that of pure water
  Show Answer
  The correct answer is C .
• Question 108: Ethanol reacts with excess acidified K₂Cr₂O to produce Options:
  A) ethanedioic acid
  B) ethanal
  C) ethylethanoate
  D) ethanoic acid
  Show Answer
  The correct answer is D .
• Question 109: An anhydride is Options:
  A) a compound wich has no water of crystallization
  B) an oxide whose solution in water has a PH greater than 7
  C) an oxide whose solution in water has a PH less than 7
  D) an oxide that has hydrogen atoms
  E) an amphoteric oxide
  Show Answer
  The correct answer is C .
• Question 110: How many protons, neutrons and electrons respectively are present in the element 60/27 Co? Options:
  A) 27, 33 and 33
  B) 33, 27 and 27
  C) 27, 33, and 27
  D) 60, 33 and 60
  Show Answer
  The correct answer is C .