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 231: Which of the following types of alkanols undergo oxidation to produce alkanoic acids? 1. Primary alkanols 11. Secondary alkanols 111. Tertiary alkanols Options:
  A) 1,11 and 111
  B) l and ll only
  C) ll only
  D) l only
  Show Answer
  The correct answer is D .
• Question 232:

  

  Use the diagram to answer this question.

  The gas that can be used to demonstrate the experiment is

  Options:
  A) hydrogen chloride
  B) hydrogen sulphide
  C) nitrogen(ll) oxide
  D) dinitrogen (l) oxide
  Show Answer
  The correct answer is A .
• Question 233: In a neutralization reaction involving HCI and NaOH using litmus as indicator, the colour at the end point is Options:
  A) Blue
  B) Red
  C) Orange
  D) Purple
  Show Answer
  The correct answer is C .
• Question 234: Sodium hydroxide solution can be conveniently stored in a container made of? Options:
  A) lead
  B) zinc
  C) aluminium
  D) copper
  Show Answer
  The correct answer is D .
• Question 235:

  When a solid substance disappears completely as a gas on heating, the substance is said to have undergone?

  Options:
  A) Sublimation
  B) Crystallization
  C) Distillation
  D) Evaporation
  Show Answer
  The correct answer is A .
• Question 236: Due to the high reactivity of sodium, it is usually stored under Options:
  A) water
  B) mercury
  C) paraffin
  D) phenol
  Show Answer
  The correct answer is C .
• Question 237:

  2H₂ + O₂2 → H₂+O ΔH = -571kJ

  In the equation above, how much heat will be liberated if 12.0g of hydrogen is burnt in excess oxygen?

  Options:
  A) -1142 kJ
  B) -571 kJ
  C) +1142 kJ
  D) -1713 kJ
  Show Answer
  The correct answer is D .
• Question 238:

  The following non-metal form acidic oxides with oxygen except?

  Options:
  A) phosphorus
  B) sulphur
  C) carbon
  D) chlorine
  Show Answer
  The correct answer is C .
• Question 239: If the change in free energy of a system is -899 Jmol^-1 and the entropy change is 10Jmol^-1k^-1 at 250C, calculate the enthalpy change. Options:
  A) +2081 Jmol^-1
  B) -2081 Jmol^-1
  C) -649 Jmol^-1
  D) +649 Jmol^-1
  Show Answer
  The correct answer is A .
• Question 240: The oxidation state of oxygen in tetraoxosulphate (VI) acid is Options:
  A) -4
  B) -2
  C) +4
  D) -8
  Show Answer
  The correct answer is B .