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 151: What volume of 11.0 M hydrochloric acid must be dilute to obtain 1 dm³ of 0.05 M acid? Options:
  A) 0.05 dm³
  B) 0.10 dm³
  C) 0.55 dm³
  D) 11.0 dm³
  Show Answer
  The correct answer is A .
• Question 152: SO₃ is NOT directly dissolved in water in the preparation of H₂SO₄ by the contact process because? Options:
  A) the reaction between SO₃ and water is violently exothermic
  B) acid is usually added to water and never water to acid
  C) SO₃ does not dissolve in water readily
  D) SO₃ is an acid gas
  Show Answer
  The correct answer is A .
• Question 153:

  According to the Kinetic Theory an increase in temperature causes the kinetic energy of particles to

  Options:
  A) decrease
  B) increase
  C) be zero
  D) remain constant
  Show Answer
  The correct answer is B .
• Question 154: The presence of nitrogen in air is to slow down Options:
  A) respiration and combustion
  B) combustion and corrosion
  C) corrosion and respiration
  D) respiration and transpiration
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  The correct answer is B .
• Question 155: A compound that gives a brick-red colour to a non-luminous flame is likely to contain Options:
  A) copper ions
  B) sodium ions
  C) calcium ions
  D) aluminium ions
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  The correct answer is C .
• Question 156: One of the following techniques can be used to show that chlorophyll pigment is a mixture of chemical compounds and not a single coloured compound Options:
  A) cystallization
  B) hydrolysis
  C) sublimation
  D) filtration
  E) chromatography
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  The correct answer is E .
• Question 157: On heating, which of the following compounds will decompose to the free metal, nitrogen (IV) oxide and oxygen? Options:
  A) Ca(NO₃)₂
  B) Cu(NO₃)₂
  C) AgNO₃
  D) NaNO₃
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  The correct answer is C .
• Question 158: In the reaction E+F ↔ G+H, the backward reaction is favoured if the concentration of Options:
  A) F is increased
  B) E is increased
  C) E is reduced
  D) G is reduced
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  The correct answer is C .
• Question 159: 0.1 Faraday of electricity was passed through a solution of copper (ll) sulphate. The maximum weight of copper deposited on the cathode would be [Cu = 64] Options:
  A) 64.0g
  B) 32.0g
  C) 16.0g
  D) 6.4 g
  E) 3.2g
  Show Answer
  The correct answer is E .
• Question 160: The substance that is used in the steel industry for the removal of carbon. Sulphur and phosphorus impurities from pig iron is Options:
  A) oxygen
  B) chlorine
  C) nitrogen
  D) hydrogen
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  The correct answer is A .