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 1291: When sulphur (IV) oxide is passed into a solution of sodium hydroxide for a long time, it eventually produces a solution of Options:
  A) NaHSO₄
  B) Na₂SO₃
  C) NaHSO₃
  D) Na₂SO₄
  Show Answer
  The correct answer is B .
• Question 1292:

  

  Choose the correct answer in the option above.

  Which of the following is a primary amine?

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is B .
• Question 1293: The oxidation state of oxygen on tetraoxosulphate iv acid is Options:
  A) -4
  B) -2
  C) 4
  D) -8
  Show Answer
  The correct answer is B .
• Question 1294: Which of the following statements is true about 2-methylpropane and butane Options:
  A) They have different number of carbon atoms
  B) They are members of same homologous series
  C) They have the same boiling points
  D) They have the same chemical properties
  Show Answer
  The correct answer is D .
• Question 1295: Hardness of water is mainly due to the presence of Options:
  A) calcium hydroxide or magnesium hydroxide
  B) calcium trioxocarbonate (IV) or calcium tetraoxosulphate (VI)
  C) sodium hydroxide or magnesium ydroxide
  D) calcium chloride or sodium chloride salts
  Show Answer
  The correct answer is B .
• Question 1296: An undesirable paraffin in the petroleum industry which is particularly prone to knocking is? Options:
  A) iso-octane
  B) n-heptane
  C) iso-heptane
  D) n-octane
  Show Answer
  The correct answer is B .
• Question 1297:

  The molar ratio of carbon to hydrogen of a volatile liquid compound is 1: 2. 0. 12 g of the liquid on evaporation at s.t.p. gave 32 cm³ of vapour. The molecular formula of the liquid is

  [G.M.V =22.4 dm ³, C = 12, H = 1]

  Options:
  A) C ₃ H ₆
  B) C ₄H ₈
  C) C ₅C ₁₀
  D) C ₆H ₁₂
  Show Answer
  The correct answer is D .
• Question 1298:

  Which of the following salts when dissolved in water will NOT give the corresponding pH value?

  Options:
  A) NaHSO₄, pH < 5
  B) Na₂CO₃, pH > 8
  C) Na₂Cl,pH = 7
  D) NaHCO, pH < 6
  Show Answer
  The correct answer is D .
• Question 1299: The gas that is removed by the water in the flask is Options:
  A) O ₂
  B) SO ₂
  C) HCI
  D) H ₂
  Show Answer
  The correct answer is C .
• Question 1300: When water boilers are used for long period of time, the solid substances left behind as scale are Options:
  A) magnesium trioxosilicate (IV) and rust
  B) magnesium trioxosilicate (IV) and calcium tetraoxosulphate (VI)
  C) clay and magnesium troxosulphate (IV)
  D) clay and rust
  Show Answer
  The correct answer is A .