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 1631: How many isomers does pentane have? Options:
  A) 6
  B) 5
  C) 4
  D) 3
  Show Answer
  The correct answer is D .
• Question 1632: Which of the following statements is true? When the potassium atom forms its ion Options:
  A) it gains one electron and becomes neutral
  B) its atomic number decreases
  C) it achieves electronic configuration of orgon
  D) it loses one proton
  E) it loses one neutron
  Show Answer
  The correct answer is C .
• Question 1633: Which of the following alkanes has the highest boiling point? Options:
  A) Pentane
  B) Ethane
  C) Propane
  D) Methane
  Show Answer
  The correct answer is A .
• Question 1634: A red precipitate of copper (I) carbide is formed when ammonium solution of copper (I) chloride is introduced into Options:
  A) CH₂ = CH - CH₂ - CH₃
  B) CH₃ CH₂ - C ≡ CH
  C) CH₃ CH₂ CH₂ CH₃
  D) CH₃ - C C - CH₃
  Show Answer
  The correct answer is B .
• Question 1635: Certain useful waxes are composed mainly of Options:
  A) amino acids
  B) glycerols
  C) alkanols
  D) alkanoates
  Show Answer
  The correct answer is B .
• Question 1636:

  How many electrons will be found in the nucleus of an atom with mass number 23 and 17 neutrons?

  Options:
  A) none
  B) 6
  C) 7
  D) 8
  Show Answer
  The correct answer is A .
• Question 1637: Unsaturated organic compounds are identified by decolourization of Options:
  A) silver bromine and potassium tetraoxomanganate (VII) solutions
  B) bromine water and acidified potassium tetraoxomanganate (VII) solution
  C) silver bromide solution and bromine water
  D) bromine water and alkaline potassium tetraoxomanganate (VII) solution
  Show Answer
  The correct answer is B .
• Question 1638:

  MnO_4(aq) + 8H⁺_(aq) + Y → Mn²⁺_(aq) + 4H₂O_(l)

  Y in the equation above represents

  Options:
  A) 2e^-
  B) 3e^-
  C) 5e^-
  D) 7e^-
  Show Answer
  The correct answer is C .
• Question 1639: The most volatile fraction obtained from fractional distillation of crude petroleum contains? Options:
  A) butane , propane and kerosene
  B) butane , propane and petrol
  C) ethane, methane and benzene
  D) methane, ethane and propane
  Show Answer
  The correct answer is D .
• Question 1640:

  Which of the following is a form of calcium carbonate?

  I. limestone
  II. marble
  III. chalk
  Iv. egg-shells

  Options:
  A) I only
  B) I, II and IV
  C) I and II only
  D) I, II, III, and IV
  Show Answer
  The correct answer is D .