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 1431: Which of the following represent hybridization in ethyne? Options:
  A) Sp²
  B) Sp²d
  C) Sp³
  D) Sp
  Show Answer
  The correct answer is D .
• Question 1432: In an attempt to remove sugar from a breaker containing a quantity of sand and sugar, 2 M ammonium chloride solution was accidentally added instead of water. Which of the following method could be used to remove the ammonium chloride from the mixture? Options:
  A) Fractional distillation
  B) crystallization
  C) Filtration followed by evaporation
  D) Evaporation followed by sublimation
  E) Filtration followed by sublimation
  Show Answer
  The correct answer is D .
• Question 1433: Diamond cannot be used Options:
  A) In making bicycle chains
  B) As abrasives
  C) In cutting glass and metals
  D) As dies for drawing wires
  Show Answer
  The correct answer is A .
• Question 1434:

  If the cost of electricity required to discharge 10g of an ion X${}^{3+}$ is N20.00, how much would it cost to discharge 6g of ion Y${}^{2+}$?

  [1 faraday = 96,500C, atomic masses are X = 27, Y = 24]

  Options:
  A) N10.00
  B) N6.00
  C) N20.00
  D) N9.00
  Show Answer
  The correct answer is D .
• Question 1435: The reaction between sulphur (IV) oxide and oxygen is represented by the equilibrium reaction 2SO_2(g) + O_2(g) ↔ 2SO_3(g), ∆H = -196 kJ. What factor would influence increased production of SO_3(g)? Options:
  A) Addition of a suitable catalyst
  B) Increase in the temperature of the reaction
  C) Decrease in the temperature of the reaction
  D) Decrease in the concentration of SO_2(g)
  Show Answer
  The correct answer is C .
• Question 1436: In which of the following reactions does hydrogen peroxide act as a reducing agent? Options:
  A) H₂S + H₂O₂ $\to$ S + 2H₂O
  B) PbSO₃ + H₂O₂ $\to$ PbSO₄ + H₂O
  C) 2I+ 2H⁺ + H₂O₂ $\to$ I₂ + 2H₂O
  D) PbO₂ + 2HNO₃ + H₂O₂ $\to$ Pb(NO₃)₂ + 2H₂O + O₂
  E) SO₂ + H₂O₂ $\to$ H₂SO₄
  Show Answer
  The correct answer is D .
• Question 1437:

  What is the chemical name for the compound CuCO${}_3$?

  Options:
  A) Copper (iii) carbonate
  B) Copper (ii) carbonate
  C) Copper (i) carbonate
  D) Copper
  Show Answer
  The correct answer is B .
• Question 1438: Which of the following terms indicates the number of bonds that can be formed by an atom? Options:
  A) Oxidation number
  B) Valence
  C) Atomic number
  D) Electronegativity
  Show Answer
  The correct answer is B .
• Question 1439:

  The collision theory explains reaction rates in terms of

  Options:
  A) size of the product
  B) frequency of collision of the reactants
  C) size of reactant
  D) frequency of collision of the products
  Show Answer
  The correct answer is B .
• Question 1440:

  The reactions below represent neutralization reaction, in which of them is the value of H highest?

  Options:
  A) CH${}_3$CH${}_2$COOH + KOH → CH${}_3$CH${}_2$COOK + H${}_2$O
  B) NH${}_4$OH + HCL → NH${}_4$ + H${}_2$O
  C) NaOH + HCL → NaCL + H${}_2$O
  D) CH${}_3$COOH + NaOH → CH${}_3$COONa + H${}_2$O
  Show Answer
  The correct answer is C .