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 841: Which of the following is a property of ionic chlorides? Options:
  A) They can be decomposed by heat
  B) They react with aqueous AgNO₃ to give a white precipiate which is soluble in excess ammonia
  C) They explode when in contact with dry ammonia
  D) They react with concentrated tetraoxosulphate (IV) acid to give white fumes of chlorine gas
  Show Answer
  The correct answer is B .
• Question 842:

  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 .
• Question 843:

  Identify the reducing agent in the following reaction:
  Zn + CuSO${}_4$ ZnSO${}_4$ + Cu

  Options:
  A) Cu
  B) Zn
  C) ZnSO${}_4$
  D) CuSO${}_4$
  Show Answer
  The correct answer is B .
• Question 844: Which of the following classes of organic compounds undergoes rapid oxidation with bromine water? Options:
  A) alcohols
  B) alkenes
  C) carboxylic acids
  D) esters
  E) alkanes
  Show Answer
  The correct answer is B .
• Question 845: 20 cm³ of a 2.0 M solution of ethanoic acid was added to excess of 0.05 M sodium hydroxide. The mass of the salt produced is?(Na = 23, C = 12, O = 16, H = 1) Options:
  A) 2.50 g
  B) 2.73 g
  C) 3.28 g
  D) 4.54 g
  Show Answer
  The correct answer is C .
• Question 846:

  

  Use the table above to answer this question .The least reactive element is

  Options:
  A) W
  B) X
  C) Y
  D) Z
  Show Answer
  The correct answer is D .
• Question 847: The oxidation state of oxygen on tetraoxosulphate iv acid is Options:
  A) -4
  B) -2
  C) 4
  D) -8
  Show Answer
  The correct answer is B .
• Question 848: Haematite is an ore of Options:
  A) zinc
  B) lead
  C) iron
  D) copper
  Show Answer
  The correct answer is C .
• Question 849: Which of the following equilibria is shifted to the right as a result of an increase in pressure? Options:
  A) H_2(g) + I_2(g) 2HI_(g)
  B) 2NO_2(g) N₂O_4(g)
  C) PCl_5(s) PCl_3(s) + Cl_2(g)
  D) 2O_3(g) 3O_2(g)
  Show Answer
  The correct answer is B .
• Question 850: The electron configuration of ₂₂X ²⁺ ion is Options:
  A) 1s² 2s²2p⁶ 3s² 3p⁶ 4s² 3d²
  B) 1s² 2s²2p⁶ 3s² 3p⁶ 4s² 3d¹
  C) 1s² 2s²2p⁶ 3s² 3p⁶
  D) 1s² 2s²2p⁶ 3s² 3p⁶ 4s²
  Show Answer
  The correct answer is D .