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 941: which of the following gives a precipitate when treated with NaOH solution? Options:
  A) AlCl₃
  B) NH₄Cl
  C) Na₂CO₃
  D) CH₃COONa
  Show Answer
  The correct answer is A .
• Question 942: Which of the following represents saponification? Options:
  A) Reaction of carboxylic acids with sodium hydroxide
  B) Reaction of alkanoates with acid
  C) Reaction of alkanoates with alcohols
  D) Reaction of alkanoates with sodium hydroxide
  Show Answer
  The correct answer is D .
• Question 943: 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 944:

  

  In the solubility curve above, water at 98^oC is saturated with KCL and KCIO₃ What is the percentage of KCL impurity in the crystals formed when the solution is cooled to 30 ^oC?

  Options:
  A) 51.5
  B) 45.5
  C) 34.5
  D) 26.5
  Show Answer
  The correct answer is C .
• Question 945: An example of a solid emulsion is Options:
  A) Butter
  B) Hair cream
  C) Milk
  D) Cod-liver oil
  Show Answer
  The correct answer is A .
• Question 946: Mortar is NOT used for under-water construction because Options:
  A) it hardens by lose of water
  B) its hardening doe not depend upon evaporation
  C) it requires concrete to harden
  D) it will be washed away by the flow of water
  Show Answer
  The correct answer is A .
• Question 947:

  Which of these alloys contains copper?

  Options:
  A) solder
  B) steel
  C) permallory
  D) bronze
  Show Answer
  The correct answer is D .
• Question 948: Elements in the same period in the periodic table have the same Options:
  A) number of shells
  B) atomic number
  C) chemical properties
  D) physical properties
  Show Answer
  The correct answer is A .
• Question 949:

  N₂O_4(g) ↔ 2NO_2(g)

  In the endothermic reaction above, more product formation will be favoured by

  Options:
  A) a constant volume
  B) an increase in pressure
  C) a decrease in pressure
  D) a decrease in volume
  Show Answer
  The correct answer is C .
• Question 950: The relative atomic mass of a naturally occurring lithium consisting of 90%$\frac{7}{3}$Li and 10%$\frac{6}{3}$Li is Options:
  A) 6.2
  B) 6.8
  C) 7.1
  D) 6.9
  Show Answer
  The correct answer is D .