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 171:

  2Na ₂ O _2(s) + 2H ₂ O ₂₍₁₎ → 4 NaOH_(s) +O_2(s)

  The substance that is oxidized in the reaction above is

  Options:
  A) 2NaO_2(s)
  B) NaOH(aq)
  C) H₂O₍₁₎
  D) O_2(g)
  Show Answer
  The correct answer is A .
• Question 172:

  Which of the following is an example of a chemical change?

  Options:
  A) dissolution of salt in water
  B) rusting of iron
  C) melting of ice
  D) separating a mixture by distillation
  Show Answer
  The correct answer is B .
• Question 173: Hydrogen is readily released when dilute hydrochloric acid reacts with Options:
  A) Cu
  B) Na
  C) Au
  D) Ag
  Show Answer
  The correct answer is B .
• Question 174:

  An organic compound that does not undergo a reaction with both hydrogen cyanide and hydroxylamine can be?

  Options:
  A) Alkene
  B) Alkanal
  C) Alkanone
  D) Alkanoic Acid
  Show Answer
  The correct answer is A .
• Question 175:

  Which type of chemical combination involves the transfer of electrons from one atom to another, resulting in the formation of oppositely charged ions?

  Options:
  A) Ionic bonding
  B) Hydrogen bonding
  C) Covalent bonding
  D) Metallic bonding
  Show Answer
  The correct answer is A .
• Question 176:

  A metal M displaces zinc from ZnCl, solution, solution

  This shows that

  Options:
  A) electrons flow from zinc to M
  B) M is more electropositive than zinc
  C) M is more electonegative than zinc
  D) zinc is more electropositive than M
  Show Answer
  The correct answer is B .
• Question 177: Which of the following can have an isomer? Options:
  A) C₂H₄
  B) C₄H₁₀
  C) C₃H₈
  D) C₂H₆
  E) C₆H₆
  Show Answer
  The correct answer is B .
• Question 178: The compound produced when sodium peroxide is heated with excess sodium is Options:
  A) Na₂CO₃
  B) Na₂O
  C) NaNO₂
  D) NaOH
  Show Answer
  The correct answer is B .
• Question 179:

  1.00 g of the oxide of metal X (atomic mass = 64) gave 0.80 g of the metal when reduced with hydrogen.

  The formula of the oxide is?

  Options:
  A) X₂O
  B) XO
  C) XO₂
  D) X₂O₃
  E) X₃O₄
  Show Answer
  The correct answer is B .
• Question 180: The reaction between ethanoic acid and sodium hydroxide is an example of Options:
  A) esterification
  B) neutralization
  C) hydroxylation
  D) hydrolysis
  Show Answer
  The correct answer is B .