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 2061: Which of the following is used in fire extinguishers? Options:
  A) Carbon (ll) oxide
  B) Carbon (lV) oxide
  C) Sulphur (lV) oxide
  D) Ammonia
  Show Answer
  The correct answer is B .
• Question 2062: What volume of 0.5 mol dm^-3 H₂SO₄ will exactly neutralize 20cm³ of 0.1 mol dm^-3 NaOH solution? Options:
  A) 2.0 cm³
  B) 5.0 cm³
  C) 6.8 cm³
  D) 8.3 cm³
  Show Answer
  The correct answer is A .
• Question 2063:

  The solubility of Na₃AsO₄(H₂O)₁₂ is 38.9g per 100g H₂O. What is the mass percentage of Na₃AsO₄ in the saturated solution?

  (As = 75, Na = 23, O = 16, H = 1)

  Options:
  A) 87.27%
  B) 38.9%
  C) 19.1%
  D) 13.7%
  Show Answer
  The correct answer is C .
• Question 2064: Chlorine, bromine and iodine resemble one another in that they Options:
  A) dissolve in alkalis
  B) react violently with hydorgen without heating
  C) are liquids
  D) displace one another from solutiions of their salts
  Show Answer
  The correct answer is D .
• Question 2065: Copper sulphate solution is electolysed using platinum electrodes A. current of 0.193 amperes is passed for 2hrs. How many grams of copper are deposited? (cu = 63.5, F = 96500 coulombs) Options:
  A) 0.457g
  B) 0.500g
  C) 0.882g
  D) 0.914g
  E) 1.00g
  Show Answer
  The correct answer is A .
• Question 2066: Which of the following has an isomer? Options:
  A) C₆H₆
  B) C₂H₆
  C) C₄H₁₀
  D) C₂H₄
  Show Answer
  The correct answer is C .
• Question 2067:

  

  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 2068: The flame used by welders in cutting metals is Options:
  A) butane gas flame
  B) acetylene flame
  C) kerosene flame
  D) oxy-acetylene flame
  E) oxygen flame
  Show Answer
  The correct answer is D .
• Question 2069:

  1s², 2s², 2p⁶, 3s², 3p⁶, 3d⁷, 4s²

  An element with the electronic configuration above is a

  Options:
  A) non-metal
  B) metal
  C) transition element
  D) group two element
  Show Answer
  The correct answer is C .
• Question 2070:

  When a substance is oxidized, it

  Options:
  A) Loses electrons
  B) Gains oxygen atoms
  C) Gains electrons
  D) Loses protons (H+ ions)
  Show Answer
  The correct answer is A .