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 2111: Hydrogen sulphide gas can act as Options:
  A) an oxidizing agent
  B) a dehydrating agent
  C) a bleaching agent
  D) a precipitating agent
  Show Answer
  The correct answer is D .
• Question 2112: A balanced chemical equation obeys the law of? Options:
  A) conservation of mass
  B) difinite proportions
  C) multiple proportions
  D) conservation of energy
  Show Answer
  The correct answer is A .
• Question 2113: Which of the following questions is correct about the periodic table? Options:
  A) The non-metallic properties of the elements tend to decrease across each period
  B) The valence electrons of the elements increase progressively across the period
  C) Elements in the same group have the same numbeer of electron shells
  D) Elements in the same period have the number of valence electrons
  Show Answer
  The correct answer is B .
• Question 2114:

  In a reaction: SnO + 2C → Sn + 2CO, the mass of coke containing 80% carbon required to reduce 0.302 kg of pure tin oxide is?

  (Sn - 119, O - 16, C - 12).

  Options:
  A) 0.40 kg
  B) 0.20 kg
  C) 0.06 kg
  D) 0.04 kg
  Show Answer
  The correct answer is C .
• Question 2115: Palm wine turns sour with time because? Options:
  A) the sugar content is converted into alcohol
  B) the carbon (IV) oxide formed during the fermentation process has a sour taste
  C) it is commonly adulterated by the tappers and sellers
  D) microbial activity results in the production of orgain acids within it
  Show Answer
  The correct answer is D .
• Question 2116: Complete hydrogenation of ethyne yields? Options:
  A) benzene
  B) methane
  C) ethane
  D) ethene
  E) propane
  Show Answer
  The correct answer is C .
• Question 2117: Oxygen-demanding waste are considered to be a water pollutant because they? Options:
  A) deplete oxygen which is necessary for the survival of aquatic organism
  B) increase oxygen which is necessary for survival of aquatic organism
  C) increase other gaseous substances which are necessary for the survival of aquatic organisms
  D) deplete other gaseous species which is necessary for the survival of aquatic organisms
  Show Answer
  The correct answer is A .
• Question 2118: Duralumin consists of aluminium, copper, ? Options:
  A) zinc and gold
  B) lead and maganese
  C) nickle and silver
  D) manganese and magnesium
  Show Answer
  The correct answer is D .
• Question 2119: The constituent common to duralumin and alnico is Options:
  A) Co
  B) Mn
  C) Al
  D) Mg
  Show Answer
  The correct answer is C .
• Question 2120: Oxidation of concentrated hydrochloric acid with manganese (IV) oxide liberates a gas used in the? Options:
  A) manufacture of tooth pastes
  B) treatment of simple golitre
  C) vulcanization of rubber
  D) sterilization of water
  Show Answer
  The correct answer is D .