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 321: The importance of sodium aluminate (III) in the treatment of water is to Options:
  A) cause coagulation
  B) neutralize acidity
  C) prevent goitre and tooth decay
  D) kill germs
  Show Answer
  The correct answer is A .
• Question 322: Ethanol reacts with excess acidified K₂Cr₂O to produce Options:
  A) ethanedioic acid
  B) ethanal
  C) ethylethanoate
  D) ethanoic acid
  Show Answer
  The correct answer is D .
• Question 323:

  4g each of aluminium foil and aluminium powder were introduced respectively into flasks P and Q.

  Flask P was treated with warm bench sodium hydroxide and all the aluminium dissolved in one hour. Flask Q was treated with cold sodium hydroxide and all the aluminium dissolved in 10 minutes. What was responsible for Q reacting faster than P?

  Options:
  A) There were more aluminium atoms in Q than P
  B) The heat given off in retarded the reaction
  C) Q generated more pressure than P during the reaction
  D) P generated more pressure than Q
  E) Q has a greater surface area for the reaction than P
  Show Answer
  The correct answer is E .
• Question 324: 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 325: Elements in the same period in the periodic table have the same Options:
  A) number of shells
  B) atomic number
  C) chemical properties
  D) physical properties
  Show Answer
  The correct answer is A .
• Question 326:

  ZnO_(s) + CO_(g) → Zn_(s) + CO_2(g)

  In the reaction above, Zinc has been

  Options:
  A) decomposed
  B) displaced
  C) oxidized
  D) reduced
  Show Answer
  The correct answer is D .
• Question 327:

  The nucleus of an atom consists of?

  Options:
  A) Electrons and neutrons
  B) Electrons and protons
  C) Protons and neutrons
  D) None of the above
  Show Answer
  The correct answer is C .
• Question 328: An element with atomic number twelve is likely to be Options:
  A) electrovalent with a velocity of 1
  B) electrovalent with a valency of 2
  C) covalent with a valency of 2
  D) covalent with valency of 4
  Show Answer
  The correct answer is B .
• Question 329: An element X has electron configuration 1s² 2s² 2p⁶ 3s² 3p⁵. Which of the following statements is correct about the element? Options:
  A) lt has a completely filled p-orbital
  B) lt has 5 electrons in its outermost shell.
  C) lt belongs to group ll on the periodic table
  D) lt is a halogen
  Show Answer
  The correct answer is D .
• Question 330:

  Chromatography is used to separate components of mixture which differ in their rates of ?

  Options:
  A) diffusion
  B) migration
  C) reaction
  D) sedimentation
  Show Answer
  The correct answer is B .