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 661:

  What is the valency of an element with the electronic configuration 2, 8, 7?

  Options:
  A) 7
  B) 1
  C) 2
  D) 3
  Show Answer
  The correct answer is B .
• Question 662: In the extraction of iron in the blast furnace, limestone is used to? Options:
  A) release CO₂ for the reaction
  B) reduce the iron ore
  C) increase the strenght of the iron
  D) remove impurities
  Show Answer
  The correct answer is D .
• Question 663: The highest rate of production of carbon (lV) oxide can be achieved using Options:
  A) 0.05 mol ^-3HCI and 5g powdered CaCO₃
  B) 0.05 mol ^-3HCI and 5g lump CaCO₃
  C) 0.10 mol ^-3HCI and 5g powdered CaCO₃
  D) 0.025 mol ^-3HCI and 5g powdered CaCO₃
  Show Answer
  The correct answer is C .
• Question 664: Commercial bleaching can be carried out using Options:
  A) sulphur (IV) oxide and ammonia
  B) hydrogen sulphide and chlorine
  C) chlorine and sulphur (IV) oxide
  D) ammonia and chlorine
  Show Answer
  The correct answer is C .
• Question 665: The weakest attractive force that can be observed between two molecules is Options:
  A) ionic
  B) covalent
  C) co-ordinate covalent
  D) vander Waals
  Show Answer
  The correct answer is D .
• Question 666:

  Hydrogen bond is a sort of

  Options:
  A) van der waals force
  B) dative bond
  C) ionic bond
  D) a covalent bond
  Show Answer
  The correct answer is D .
• Question 667:

  Which of the following compounds is an example of an electrovalent bond?

  Options:
  A) NaCl (sodium chloride)
  B) CO2 (carbon dioxide)
  C) H2O (water)
  D) CH4 (methane)
  Show Answer
  The correct answer is A .
• Question 668:

  

  Which of the curves shown in the figure given represents the relationships between the volume(V) and pressure(P) of an ideal gas at constant temperature?

  Options:
  A) 1
  B) 2
  C) 3
  D) 4
  E) 1 and 3
  Show Answer
  The correct answer is C .
• Question 669: The compounds CH₃CH₂CHO and CH₃COCH₃ can be distinguished from each other using Options:
  A) Dilute ammonia
  B) Benedict's solution
  C) Tollen's reagent
  D) Sodium hydroxide solution
  Show Answer
  The correct answer is C .
• Question 670: Two organic compounds K and L were treated with a few drops of Fehling's solutions respectively . K formed a brick-red precipitate while L, remains unaffected. The compound K is an Options:
  A) alkanol
  B) alkane
  C) alkanal
  D) alkanone
  Show Answer
  The correct answer is C .