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 11: Lucas reagent is used to test for Options:
  A) alkanes
  B) alkanoic acids
  C) alkanols
  D) amines
  Show Answer
  The correct answer is C .
• Question 12: The oxide that remains unchanged when heated in hydrogen is? Options:
  A) CuO
  B) Fe₂O₃
  C) PbO₂
  D) ZnO
  Show Answer
  The correct answer is B .
• Question 13: In the electrolysis of a concentrated solution of sodium chloride using electrodes, which of the following ions are discharged at the cathode and anode respectively? Options:
  A) Na⁺ and Cl^-
  B) Na⁺ and OH^-
  C) H⁺ and OH^-
  D) H⁺ and Cl^-
  Show Answer
  The correct answer is D .
• Question 14: The formula for ethyl butanoate is Options:
  A) C₃H₇COOC₂H₅
  B) C₂H₅COOC₃H₇
  C) C₄H₉COOC₂H₅
  D) C₂H₅COOC₄H₉
  Show Answer
  The correct answer is A .
• Question 15: Four elements W, X, Y and Z have atomic number 2,6,16 and 20 respectively. Which of these elements is a metal? Options:
  A) X
  B) W
  C) Z
  D) Y
  Show Answer
  The correct answer is C .
• Question 16:

  A current of 10.0A was passed for 1 hour through a solution of copper (ll) sulphate between the copper electrodes. Which of the following observation would be correct?

  (1 Faraday = 96,500 coulobms) (i) 0.186 mole of copper is dissolved from the anode. (ii) 0.372 mole of copper is deposited on the cathode. (iii) the original Cu²⁺ ion concentration of the solution remains unchanged. (iv) the original Cu²⁺ ion concentration of the solution decreases.

  Options:
  A) i and ii
  B) i and iii
  C) i and iv
  D) ii and iii
  E) ii and iv
  Show Answer
  The correct answer is B .
• Question 17:

  Which of the following statements is correct about the periodic table?

  Options:
  A) Elements in the same period have the same number of valence electrons
  B) The valence electrons of the elements in the same period increase progressively across the period
  C) Elements in the same group have the same number of electron shells
  D) The non-metallic Properties of the elements tend to decrease across each period
  Show Answer
  The correct answer is B .
• Question 18:

  Elements in the periodic table are arranged in the order of their

  Options:
  A) atomic numbers
  B) metallic character
  C) mass number
  D) relative atomic mass
  Show Answer
  The correct answer is A .
• Question 19: Aluminium hydroxide is used in the dyeing industry as a Options:
  A) dye
  B) dispersant
  C) salt
  D) mordant
  Show Answer
  The correct answer is D .
• Question 20: When steam is passed over red-hot carbon, the substances produced are Options:
  A) Hydrogen and trioxocarbonate (IV) acid
  B) Hydrogen, oxygen and carbon (IV) oxide
  C) Hydrogen and carbon (II) oxide
  D) Hydrogen and carbon (IV) oxide
  Show Answer
  The correct answer is C .