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:

  

  From the above diagram, the caustic soda in the conical flask serves to

  Options:
  A) dry ethene gas
  B) remove carbon (iv) oxides from ethene
  C) remove carbon (ii) oxide from ethene
  D) remove sulphur (iv) oxide from ethene
  Show Answer
  The correct answer is C .
• Question 1292:

  MnO^-4_(aq) + Y + 5Fe²⁺_(aq) → Mn²⁺_(aq) + 5Fe²⁺_(aq) + 4H₂O_(l)
  In the equation above, Y is

  Options:
  A) 5H⁺_(aq)
  B) 4H⁺_(aq)
  C) 10H⁺_(aq)
  D) 8H⁺_(aq)
  Show Answer
  The correct answer is D .
• Question 1293: The bleaching action of chlorine gas is effective due to the presence of Options:
  A) hydrogen chloride
  B) water
  C) air
  D) oxygen
  Show Answer
  The correct answer is B .
• Question 1294:

  At room temperature and standard pressure, chlorine gas is in which state of matter?

  Options:
  A) Plasma
  B) Solid
  C) Liquid
  D) Gas
  Show Answer
  The correct answer is D .
• Question 1295: 3.0g of a mixture of potassium carbonate and potassium chloride were dissolved in a 25cm³ of this solution required required 40.00cm₃ of 0.1M HCl for neutralization. What is the percentage by weight of K₂CO₃ in the mixture. (K = 39, O = 16, C = 12) Options:
  A) 60
  B) 72
  C) 82
  D) 89
  E) 92
  Show Answer
  The correct answer is E .
• Question 1296: The type of reaction that is peculiar to benzene is Options:
  A) addition
  B) hydrolysis
  C) polymerization
  D) substitution
  Show Answer
  The correct answer is D .
• Question 1297:

  The constituent common to duralumin and alnico is

  Options:
  A) Co
  B) Mn
  C) Al
  D) Mg
  Show Answer
  The correct answer is C .
• Question 1298: What is the valence shell electron configuration of the element with atomic number 17? Options:
  A) 1s² 2s² 2p⁶ 3s² 3p⁴
  B) 1s² 2s² 2p⁶ 3s² 3p⁵
  C) 2s² 2p⁶
  D) 3s² 3p⁵
  Show Answer
  The correct answer is B .
• Question 1299:

  What mass of water is produced when 8.0g of hydrogen reacts with excess oxygen?

  [H = 1, O = 16]

  Options:
  A) 36.0g
  B) 8.0g
  C) 72.0g
  D) 16.0g
  Show Answer
  The correct answer is C .
• Question 1300: Calcium hydroxide and ammonium chloride when heated together will give an important product. This compound may be obtained dry by Options:
  A) dissolving it in water, recrystallizing it and then drying in the oven
  B) passing it through a concentrated aqueous solution of sodium hydroxide
  C) passing it through calcium oxide
  D) passing it through concentrated sulphuric acid
  E) passing it through anhydrous calcium choride
  Show Answer
  The correct answer is C .