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 1681: An organic compound containing 40.1% carbon and 6.6% hydrogen has an empirical formula of? Options:
  A) C₂H₄O₂
  B) C₂H₃O₂
  C) CH₂O
  D) CH₃O
  Show Answer
  The correct answer is C .
• Question 1682: Transition metals possess variable oxidation states because they have Options:
  A) Electrons in the d orbitals
  B) Electron in the s orbitals
  C) A variable number of electrons in the p orbitals
  D) Partially filled p orbitals
  Show Answer
  The correct answer is A .
• Question 1683: Which of the following in aqueous solution is neutral to litmus? Options:
  A) NH₄CI
  B) NaCO₃
  C) FeCl₃
  D) NaCl
  Show Answer
  The correct answer is D .
• Question 1684:

  

  The functional groups present in the compound above are

  Options:
  A) Alkene and halo-group
  B) Hydroxyl and chloro-group
  C) Alkene and chloro-group
  D) Hydroxyl and halo-group
  Show Answer
  The correct answer is B .
• Question 1685: When sodium is added to ethanol, the products are? Options:
  A) sodium hydroxide and water
  B) sodium hydroxide and hydrogen
  C) sodium ethoxide and water
  D) sodium ethoxide and hydrogen
  Show Answer
  The correct answer is D .
• Question 1686: Stainless steel is an alloy of? Options:
  A) Iron, carbon and silver
  B) iron, carbon and lead
  C) iron, carbon and chromium
  D) iron and carbon only
  Show Answer
  The correct answer is C .
• Question 1687:

  Consider the equation below:

  Cr${}_2$O${}_7^{2-}$ + 6Fe${}^{2+}$ + 14H${}^{+}$ $\to$ 2Cr${}^{3+}$ + 6Fe${}^{3+}$ + 7H${}_2$O.

  The oxidation number of chromium changes from

  Options:
  A) +5 to +3
  B) +6 to +3
  C) -2 to +3
  D) +7 to +3
  Show Answer
  The correct answer is B .
• Question 1688: The industrial preparation of hydrogen gas from water gas is referred to as Options:
  A) Bosch process
  B) Contact process
  C) Haber process
  D) Bayer Process
  Show Answer
  The correct answer is A .
• Question 1689: Flow of current in electrolytes is due to the movement of Options:
  A) electrons
  B) Holes and electron
  C) Ions
  D) Charges
  Show Answer
  The correct answer is C .
• Question 1690: When a current I was passed through an electrolyte solution for 40 minutes, a mass X g of a univalent metal was deposited at the cathode. What mass of the metal will be deposited when a current 2I is passed through the solution for 10 minutes? Options:
  A) X/4 g
  B) X/2 g
  C) 2X g
  D) 4X g
  Show Answer
  The correct answer is B .