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 601:

  What is the product of the electrolysis of aqueous sodium chloride (NaCl) using inert electrodes?

  Options:
  A) Hydrogen gas at the cathode and chlorine gas at the anode
  B) Hydrogen gas at the cathode and oxygen gas at the anode
  C) Sodium metal at the cathode and chlorine gas at the anode
  D) Sodium metal at the cathode and oxygen gas at the anode
  Show Answer
  The correct answer is A .
• Question 602: An acid is said to be weak if? Options:
  A) its ions are so completely dissociated that they easily drift apart
  B) the acid is not corrosive
  C) the acid has low specific gravity
  D) its ions move very slowly when in solution
  E) its ions are incompletely dissociated
  Show Answer
  The correct answer is E .
• Question 603:

  The size (diameter) of five elements are in the order R < T < W < X < Y, Y being the largest. If each atom has an electron situated on its circumference, and neglecting other factors, which of the atoms will lose its electron most reluctantly?

  Options:
  A) R
  B) T
  C) W
  D) X
  E) Y
  Show Answer
  The correct answer is A .
• Question 604: Which of the following are structural isomers? Options:
  A) propanoic acid and propan-1, 2-diol
  B) Propanal and propanone
  C) Ethanoic acid and propanoic acid
  D) Ethan-1, 2-diol and ethanoic acid
  Show Answer
  The correct answer is B .
• Question 605:

  

  For which salt in the graph above does the solubility increase most rapidly with rise in temperature?

  Options:
  A) CaSO₄
  B) KNO₃
  C) NaCl
  D) KCl
  Show Answer
  The correct answer is B .
• Question 606: The oxidation number of manganese in KMnO₄ is? Options:
  A) +1
  B) +3
  C) +5
  D) +7
  E) +2
  Show Answer
  The correct answer is D .
• Question 607: 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 608: In general, an increase in temperature increases the solubility of a solute in water because? Options:
  A) more solute molecules collide with each other
  B) most solutes dissolve with the evoltion of heat
  C) more solute molecules dissociate at hihger temperatures
  D) most solutes dissolve with absorption of heat
  Show Answer
  The correct answer is C .
• Question 609: Zinc and carbon rods are used as anode and cathode respectively in a Options:
  A) Leclanche cell
  B) lead accumulator
  C) Daniel cell
  D) voltaic cell
  Show Answer
  The correct answer is A .
• Question 610:

  An element has an atomic number of 8 and a mass number of 16. How many neutrons does this element have?

  Options:
  A) 24
  B) 16
  C) 8
  D) 32
  Show Answer
  The correct answer is C .