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 201:

  An electron can be added to a halogen atom to form a halide ion with?

  Options:
  A) 8 valence electrons
  B) 7 valence electrons
  C) 2 valence electrons
  D) 3 valence electrons
  Show Answer
  The correct answer is A .
• Question 202:

  

  The compound above contains

  Options:
  A) Sp ³ hybridized carbon atoms only
  B) Sp ² hybridized carbon atoms only
  C) Sp ³ and Sp hybirdized carbon atoms
  D) Sp ³ and Sp ²
  Show Answer
  The correct answer is D .
• Question 203:

  

  The diagram above represents the formation of

  Options:
  A) a metallic bond
  B) an electrovalent bond
  C) a covalent bond
  D) a coordinate covalent bond
  Show Answer
  The correct answer is C .
• Question 204: Mineral acids are usually added to commercial hydrogen peroxide to Options:
  A) oxidize it
  B) decompose it
  C) minimize its decomposition
  D) reduce it to water and oxygen
  Show Answer
  The correct answer is C .
• Question 205: Which of the following CANNOT be obtained by fractional distillation of petroleum? Options:
  A) Ether
  B) Methane
  C) Butane
  D) Ethene
  E) Hydrogen
  Show Answer
  The correct answer is E .
• Question 206: What current in ampere will deposit 0.27g of aluminium in 2 hours? [Al = 27, F = 96500C]. Options:
  A) 3.2
  B) 8
  C) 0.4
  D) 16
  Show Answer
  The correct answer is C .
• Question 207:

  

  In the electrolysis of aqueous solution of K₂SO ₄ in the above cell, which species migrate to the anode?

  Options:
  A) SO^2-OH ^-
  B) K ⁺ and SO ₄^2-
  C) OH and HO
  D) H₃O ⁺ and K
  Show Answer
  The correct answer is A .
• Question 208:

  Potassium trioxochlorate (V)has a solubility of 1.5 mol dm ^-3 at 45 ^oC.On cooling this solution to a temperature of 20 ^oC, the solubility was found to be 0.5 mol dm ^-3. What mass of KCIO ₃ was crystalized out?

  [K = 39, Cl = 35.5 O =16].

  Options:
  A) 1.00g
  B) 10.00g
  C) 12.25g
  D) 122.50g
  Show Answer
  The correct answer is D .
• Question 209:

  SO${}_2$ + O${}_2$ 2SO${}_3$

  In the reaction above, the most suitable catalyst is?

  Options:
  A) chromium(vi)oxide
  B) iron(iii)oxide
  C) copper(i)oxide
  D) vanadium(v)oxide
  Show Answer
  The correct answer is D .
• Question 210:

  Which of the following are chemical changes?

  I. cooking of food
  II. digestion of food
  III. freezing of water
  IV. water is heated up

  Options:
  A) I and II
  B) I, II, and III
  C) III and IV
  D) all of the above
  Show Answer
  The correct answer is A .