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 1641: The final products of the reaction between methane and chlorine in the presence of ultraviolet light are hydrogen chloride and Options:
  A) tricloromethane
  B) dichloromethane
  C) tetrachloromethane
  D) chloromethane
  Show Answer
  The correct answer is C .
• Question 1642: Which of the following compounds reacts with sodium metal as well as silver and copper salts ? Options:
  A) CH₃C Ξ C—CH₃
  B) CH₃CH₂CH₂₃>
  C) CH₃C Ξ CH
  D) CH₃CH = CH CH₃
  Show Answer
  The correct answer is C .
• Question 1643: A sample of hard water contains some calcium sulphate and calcium hydrogen carbonate. The total hardness may therefore be removed by Options:
  A) boiling the water
  B) adding excess calcium hydroxide
  C) adding a calculated amount of calcium hydroxide
  D) adding sodium carbonate
  E) adding magnesium hydroxide
  Show Answer
  The correct answer is D .
• Question 1644: The atom of an element X is represented as _z^yX. The basic chemical properties of X depends on the value of Options:
  A) Y
  B) Z
  C) Y - Z
  D) Z - Y
  Show Answer
  The correct answer is B .
• Question 1645: The chlorinated alkane often used industrially to remove grease is Options:
  A) tetrachloromethane
  B) chloromethane
  C) trichloromethane
  D) dichlorometane
  Show Answer
  The correct answer is A .
• Question 1646: The chromatography separation of ink is based on the ability of the components to Options:
  A) React with solvent
  B) React with each other
  C) Dissolve in each other in the column
  D) Move at different speeds in the column
  Show Answer
  The correct answer is D .
• Question 1647: When sulphur (IV) oxide is passed into a solution of sodium hydroxide for a long time, it eventually produces a solution of Options:
  A) NaHSO₄
  B) Na₂SO₃
  C) NaHSO₃
  D) Na₂SO₄
  Show Answer
  The correct answer is B .
• Question 1648: The energy changes accompanying the addition of an electron to a gaseous atom is called? Options:
  A) first ionization energy
  B) second ionization energy
  C) electron affinity
  D) electronegativity
  Show Answer
  The correct answer is C .
• Question 1649: Which of the following is not a member of the homologous series of the paraffins (alkanes)? Options:
  A) C₃H₈
  B) C₅H₁₂
  C) C₇H₁₆
  D) C₁₅H₃₂
  E) C₂₄H₄₈
  Show Answer
  The correct answer is E .
• Question 1650:

  A few drop of conc HCL are added to about 10cm${}^3$ of a solution of PH 3.4. The PH of the resulting mixture is?

  Options:
  A) less than 3.4
  B) greater than 3.4
  C) unaltered
  D) the same as that of the pure water
  Show Answer
  The correct answer is A .