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 1561:

  Which of the following is a redox reaction?

  Options:
  A) KCI_(aq) + H₂SO_4(aq) → KHSO_4(aq) + HCI_(aq)
  B) 2FeBr_2(aq) + Br_4(aq) → 2FeBr_3(aq)
  C) 3AgNO_(aq) + FeCl_3(aq) → 3AgCl_(aq) + Fe(NO₃)_3(aq)
  D) H₂CO_3(aq) → H₂O_(I)2- + CO_2(g)
  Show Answer
  The correct answer is B .
• Question 1562:

  Zn + 2HCL ZnCl${}_2$ + H${}_2$

  What happens to zinc in the above reaction?

  Options:
  A) oxidized
  B) a reactant
  C) reduced
  D) a metal
  Show Answer
  The correct answer is A .
• Question 1563:

  Which functional group is present in alkanals?

  Options:
  A) Carbonyl group (C=O)
  B) Hydroxyl group (-OH)
  C) Alkyl group (-R)
  D) Carboxyl group (-COOH)
  Show Answer
  The correct answer is A .
• Question 1564: When sodium trioxocarbonate (IV) decahydrate loses its water of crystallization to the atmosphere, the process is Options:
  A) deliquescence
  B) efflorescence
  C) hygroscopic
  D) effervesecence
  Show Answer
  The correct answer is B .
• Question 1565:

  What mass of magnesium would be obtained by passing a current of 2 amperes for 2 hours, through molten magnesium chloride?
  [1 faraday = 96500C, Mg = 24]

  Options:
  A) 1.12g
  B) 4.48g
  C) 1.80g
  D) 2.00g
  Show Answer
  The correct answer is C .
• Question 1566: In the electrolysis of CuSo_4(g) using platinum electrode the reaction at the anode is Options:
  A) 4H+ 4e - 2H₂
  B) 4OH^-- 4e = 2H₂O + O₂
  C) 2OH - 2e_- = 2OH
  D) 2OH^- + 2OH = 2H₂O + O₂
  Show Answer
  The correct answer is B .
• Question 1567: The solvent used for removing grease stain is Options:
  A) turpentine
  B) ammonia solution
  C) ethanol
  D) solution of borax in water
  Show Answer
  The correct answer is B .
• Question 1568:

  Hard water is water with high concentrations of dissolved ions, in particular calcium and

  Options:
  A) magnesium ions
  B) nitrogen ions
  C) phosporus ions
  D) helium ions
  Show Answer
  The correct answer is A .
• Question 1569: 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 1570:

  Which of the following is an example of a chemical change?

  Options:
  A) dissolution of salt in water
  B) rusting of iron
  C) melting of ice
  D) separating a mixture by distillation
  Show Answer
  The correct answer is B .