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 481: Which of the following is NOT correct test for the named organic compound in each case? Options:
  A) Butanoic acid solution gives effervescence with Na₂CO₃ solution
  B) Glucose when reacted with Na₂CrO₄ at 0°C will show immediate discharge of colour
  C) When but-2-ene is reacted with dilute solution of KMnO₄ the purple colour of KMnO is discharged readily even room temperature
  D) When butan-2-ol is boiled with butanoic acid with a drop of concentrated H₂SO₄ a sweet smelling liquid is produced
  Show Answer
  The correct answer is B .
• Question 482: The gas that can be collected by downward displacement of air is Options:
  A) chlorine
  B) sulphur (IV) oxide
  C) carbon (IV) oxide
  D) ammonia
  Show Answer
  The correct answer is D .
• Question 483:

  Which of the following alkaline metals react more quickly spontaneously with water?

  Options:
  A) Calcium
  B) Beryllium
  C) Magnesium
  D) Strontium
  Show Answer
  The correct answer is A .
• Question 484: A blue solid, T, which weighed 5.0g was placed on a table. After 8 hours, the resulting pink solid was found to weigh 5.5g. It can be inferred that substance T? Options:
  A) is deliquescent
  B) is hydroscopic
  C) has some molecules of water of crystallization
  D) is efflorescent
  Show Answer
  The correct answer is A .
• Question 485:

  The end products of burning a candle in the atmosphere are water and 

  Options:
  A) carbon (II) oxide
  B) sulphur (IV) oxide
  C) carbon (IV) oxide
  D) sulphur (VI) oxide
  Show Answer
  The correct answer is C .
• Question 486: Methanoic acid mixes with water in all proportions and has about the same boiling point as water which of the following methods would you adopt to obtain pure water from a mixture of stand, water and methanoic acid? Options:
  A) fractional distillation
  B) filtration followed by distillation
  C) neutralization with sodium hydroxide followed by distillation
  D) esterification with ethanol followed by distillation
  E) neutralization with sodium hydroxide followed by filtration
  Show Answer
  The correct answer is B .
• Question 487: Dynamic equilibrium describes a situation where Options:
  A) a reaction gives back the reactant
  B) te concentration of the reactant and products is equal
  C) both forward and and reverse reactions proceed at the same rate
  D) reactants are converted to products
  Show Answer
  The correct answer is C .
• Question 488: If an element has the electronic configuration 1s ² 2s² 2p³ 3s² 3p⁴, it is Options:
  A) a metal
  B) an alkaline earth metal
  C) an s-block element
  D) a p-Block element
  E) a transition element
  Show Answer
  The correct answer is D .
• Question 489:

  What technique is suitable for separating a binary solution of potassium chloride and potassium trioxochlorate (V)?

  Options:
  A) Fractional crystallization
  B) Fractional distillation
  C) Filtration
  D) Evaporation
  Show Answer
  The correct answer is A .
• Question 490: Sugar is separated from its impurities by Options:
  A) precipitation
  B) crystallization
  C) distillation
  D) evaporation
  Show Answer
  The correct answer is B .