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 1661: A decrease in atomic size and an increase in nuclear charge across a period lead to Options:
  A) an increase in the tendency to lose electron
  B) an increase in chemical reactivity
  C) a decrease in electropositivity
  D) a decrease in covalency in bond formation
  Show Answer
  The correct answer is B .
• Question 1662:

  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 1663: Which of the following molecules has two other positional isomers? Options:
  A) CH₃CH₂Br
  B) CH₃CHBrCH₃
  C) CBr₂F₂
  D) CH₂CHBrCH₂Br
  Show Answer
  The correct answer is D .
• Question 1664:

  Hydrocarbons which will react with Tollen's reagent conform to the general formula

  Options:
  A) C${}_n$H${}_{2n}$
  B) C${}_n$H${}_{2n+2}$
  C) C${}_n$H${}_{2n-2}$
  D) C${}_n$H${}_{2n+1}$OH
  Show Answer
  The correct answer is C .
• Question 1665: 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 1666: If 30cm³ of oxygen diffuses through porous plug in 7s, how long will it take 60 cm³ of chlorine to diffuse through the same plug? Options:
  A) 12s
  B) 14s
  C) 21s
  D) 30s
  Show Answer
  The correct answer is C .
• Question 1667: When the two end alkyl groups ethyl ethanoate are interchange, the compound formed is known as Options:
  A) methyl ethanoate
  B) ethyl propanaote
  C) methyl propanoate
  D) propyl ethanoate
  Show Answer
  The correct answer is C .
• Question 1668: 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
  Show Answer
  The correct answer is C .
• Question 1669: The label on a reagent bottle containing a clear organic liquid dropped off.The liquid was neutral to litmus and gave a colourless gas with metallic sodium. The liquid must be an? Options:
  A) alkanoate
  B) alkaene
  C) alkanol
  D) alkane
  Show Answer
  The correct answer is C .
• Question 1670: Which of the following are isomers? Options:
  A) Ethanol and dimethyl ether
  B) Benzene and methybenzene
  C) Ethanol and propanone
  D) Trichloromethane and tetrachloromethane
  Show Answer
  The correct answer is A .