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 1841: Which of the following oxides of nitrogen is unstable in air? Options:
  A) NO₂
  B) NO
  C) N₂O₄
  D) N₂O_5-
  Show Answer
  The correct answer is B .
• Question 1842: Argon is used in gas-filled electric lamp because it helps to? Options:
  A) prevent the reduction of the lamp fillaments
  B) prevent oxidation of the lamp fillaments
  C) make the lamp fillament glow brightly
  D) keep the atmosphere in the lamp inert
  Show Answer
  The correct answer is C .
• Question 1843: The salt formed from strong acid and a strong base is Options:
  A) complex
  B) neutral
  C) basic
  D) acidic
  Show Answer
  The correct answer is B .
• Question 1844: The type of iron that is best suited for welding, making nails, chains and iron rods is Options:
  A) pig iron
  B) wrought iron
  C) cast iron
  D) iron pyrites
  Show Answer
  The correct answer is B .
• Question 1845: Which experiment led to the measurement of the charge on an electron? Options:
  A) Mass spectrometric experiment
  B) Oil-drop experiment
  C) Scattering α - particles
  D) Discharge-tube experiment
  Show Answer
  The correct answer is B .
• Question 1846: If sulphur (IV) oxide and methane are released simultaneously at the opposite ends of a narrow tube, the rates of diffusion Rso₂ and Rch₄ will be in the ratio? (S = 32, O = 16, C = 12, H = 1) Options:
  A) 4:1
  B) 2:1
  C) 1:2
  D) 1:4
  Show Answer
  The correct answer is C .
• Question 1847:

  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 1848: 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 1849:

  The percentage of water of crystallization in ZnSO₄.7H₂O is

  [Zn = 65, S = 32, O = 1, H = 1]

  Options:
  A) 33%
  B) 44%
  C) 55%
  D) 87%
  Show Answer
  The correct answer is B .
• Question 1850: If the elements X and Y have atomic numbers 11 and 17 respectively, what type of bond can they form? Options:
  A) Dative
  B) Covalent
  C) Lonic
  D) Metallic
  Show Answer
  The correct answer is C .