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 1: An example of a polysaccharides is? Options:
  A) —dextrose
  B) mannose
  C) glucose
  D) starch
  Show Answer
  The correct answer is D .
• Question 2:

  An organic compound which decolorizes bromine water is likely to be?

  Options:
  A) C${}_3$H${}_8$
  B) C${}_2$H${}_6$
  C) C${}_4$H${}_{1}0$
  D) C${}_2$H${}_4$
  Show Answer
  The correct answer is D .
• Question 3: The oxidation number of manganese in KMnO₄ is? Options:
  A) +1
  B) +3
  C) +5
  D) +7
  E) +2
  Show Answer
  The correct answer is D .
• Question 4: A student prepares 0.5 M solution each of hydrochloric and ethanoic acids and then measured pH. The result would show that the? Options:
  A) pH values are equal
  B) HCI solution has a higher pH
  C) sum of the values is 14
  D) ethanoic acid solution has a higher pH
  Show Answer
  The correct answer is D .
• Question 5: The property of concentrated H₂SO₄ that makes it suitable for preparing HNO₃ is its Options:
  A) boiling point
  B) density
  C) oxidizing properties
  D) dehydrating properties
  Show Answer
  The correct answer is C .
• Question 6: A suitable solvent for iodine and nephthalene is Options:
  A) carbon (IV) sulphide
  B) ethanol
  C) water
  D) benzene
  Show Answer
  The correct answer is B .
• Question 7: Vulcanization involves the removal of Options:
  A) A monomer
  B) The single bond
  C) The double bond
  D) A polymer
  Show Answer
  The correct answer is C .
• Question 8:

  CU₂S_(s) + O_2(g) → 2CU_(s) + SO_2(g)

  What is the change in the oxidation number of copper in the reaction above?

  Options:
  A) +1 to 0
  B) 0 to +2
  C) +2 to +1
  D) 0 to +1
  Show Answer
  The correct answer is A .
• Question 9: Solutions X, Y, and Z have PH values 3.0. 5. 0 and 9. 0 respectively. Which of the following statements is correct? Options:
  A) All the solutions are acidic
  B) All the solutions are basic
  C) Y and Z are more acidic than water
  D) Y is more acidic than X
  E) Z is the least acidic
  Show Answer
  The correct answer is E .
• Question 10:

  

  Choose the correct option from the structure above

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is C .