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 41: Which of the following compounds will burn with a brick-red colour in a non-luminous Bunsen flame? Options:
  A) LiCI
  B) NaCl
  C) CaCl₂
  D) MgCl₂
  Show Answer
  The correct answer is C .
• Question 42:

  3Cu + pHNO₃ →3Cu(NO)₂ + 4H₂ O + xNO

  In the equation above, the values of p and x respectively are

  Options:
  A) 1 and 3
  B) 2 and 3
  C) 6 and 2
  D) 8 and 2
  Show Answer
  The correct answer is D .
• Question 43:

  

  Use the graph above to answer this question. The structure of cis-2-butene is

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is B .
• Question 44: Which of the following is not an alkali? Options:
  A) Ca(OH)₂
  B) NH₃
  C) NaOH
  D) Al(OH)₃
  Show Answer
  The correct answer is B .
• Question 45: 12 g of solid protassium chlorate (KCIO) were added to 40 g of water and heated to dissolve all the solid. As the solution cools, crystals of potassium chlorate at 66 ^oC. The solubility of potassium chlorate at 66 ^oC is therefore Options:
  A) 66
  B) 33
  C) 10
  D) 20
  E) 30
  Show Answer
  The correct answer is E .
• Question 46:

  The following are isoelectronic ions except

  Options:
  A) Na${}^{+}$
  B) Mg${}^{2+}$
  C) Si${}^{2+}$
  D) O${}^{2+}$
  Show Answer
  The correct answer is C .
• Question 47: Which of these require crystallization most? Options:
  A) Drug making
  B) Cement making
  C) Paint making
  D) Perfume making
  Show Answer
  The correct answer is A .
• Question 48: For a given solute, the concentration of its saturated solution in different solvents are Options:
  A) the same at the same temperature
  B) different at the same temperature
  C) the same at different temperature
  D) constant
  Show Answer
  The correct answer is B .
• Question 49:

  

  In the solubility curve above, water at 98^oC is saturated with KCL and KCIO₃ What is the percentage of KCL impurity in the crystals formed when the solution is cooled to 30 ^oC?

  Options:
  A) 51.5
  B) 45.5
  C) 34.5
  D) 26.5
  Show Answer
  The correct answer is C .
• Question 50:

  What happens when alkanoic acids react with alcohols in the presence of an acid catalyst?

  Options:
  A) Saponification
  B) Esterification
  C) Polymerization
  D) Hydrolysis
  Show Answer
  The correct answer is B .