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 111: In the purification of impure samples of ethyl ethanoate synthesized by esterification, concentrated sodium trioxocarbonate (IV) solution is used to remove Options:
  A) water
  B) basic impurities
  C) acidic impurities
  D) ethoxyethane
  Show Answer
  The correct answer is C .
• Question 112: An isotope has an atomic number of 15 and a mass number of 31. The number of proton it contains is Options:
  A) 16
  B) 15
  C) 31
  D) 46
  Show Answer
  The correct answer is B .
• Question 113: The radioactive emission with the least ionization power is Options:
  A) $\alpha -particles$
  B) X-rays
  C) $\gamma -rays$
  D) $\beta -rays$
  Show Answer
  The correct answer is C .
• Question 114: To obtain pure carbon (II) oxide from its mixture with carbon (IV) oxide, the mixture should be Options:
  A) passed over heated copper (II) oxide
  B) bubbled through water
  C) bubbled through concentrated tetroxosulphate (VI) acid
  D) bubbled through sodium hydroxide
  Show Answer
  The correct answer is D .
• Question 115: What will happen if an aluminium spoon is used to stir a solution of iron (II) trioxonitrates (V)? Options:
  A) The spoon will be oxidized while the iron (II) ions will be reduced to the metal
  B) The spoon will increase in size
  C) The spoon will be reduced while the iron (II) ions will be oxidized
  D) The spoon will be reduced
  Show Answer
  The correct answer is A .
• Question 116: Clothes should be properly rinsed with water after bleaching because Options:
  A) the bleach decolourizes the clothes
  B) chlorine reacts with fabrics during bleaching
  C) the clothes are sterilized during bleaching
  D) hydrogen chloride solution is produced during bleaching
  Show Answer
  The correct answer is D .
• Question 117: The fuming of kettles is caused by the presence in the water of Options:
  A) Calcium tetraoxosulphate (VI)
  B) Calcium hydrogentrioxocarbonate (IV)
  C) Calcium hydroxide
  D) Calcium trioxocarbonate (IV)
  Show Answer
  The correct answer is B .
• Question 118: When a bottle of Coca-Cola is opened, bubbles of evolve. The gas is? Options:
  A) hydrogen
  B) carbon monoxide
  C) carbon dioxide
  D) sulphur oxide
  E) chlorine
  Show Answer
  The correct answer is C .
• Question 119: Beryllium and aluminium have similar properties because they Options:
  A) are both metals
  B) belong to the same group
  C) belong to the same period
  D) are positioned diagonally to each other
  Show Answer
  The correct answer is D .
• Question 120: To make coloured glasses, small quantities of oxides of metals which form coloured silicates are often added to the reaction mixture consisting of Na₂CO₃ and SiO₂. Such a metals is a?. Options:
  A) pottasium
  B) barium
  C) zinc
  D) copper
  Show Answer
  The correct answer is D .