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 1651: Alkanals can be differentiated from alkanones by reaction with? Options:
  A) 2,4-dinitrophenylhydrazine
  B) hydrogen cyanide
  C) sodium hydrogen sulphite
  D) Tollen's reagent
  Show Answer
  The correct answer is D .
• Question 1652: A piece of sea shell, when dropped into a dilute solution of hydrochloric acid, produces a colourless, odourless gas which turns clear limewater milky. The sea shell contains Options:
  A) sodium chloride
  B) ammonium nitrate
  C) calcium carbonate
  D) calcium chloride
  E) magnesium chloride
  Show Answer
  The correct answer is C .
• Question 1653: When marble is heated to about 1473 K, another white solid is obtained which reacts vigorously with water to give an alkaline solution. The solution contains? Options:
  A) NaOH
  B) KOH
  C) Mg(OH)₂
  D) Zn(OH)₂
  E) Ca(OH)₂
  Show Answer
  The correct answer is E .
• Question 1654: A metallic ion X²⁺ with an inert gas structure contains 18 electrons. How many protons are there in this ion? Options:
  A) 20
  B) 18
  C) 16
  D) 2
  Show Answer
  The correct answer is A .
• Question 1655: Detergents are manufacture with strength hydrocarbon chains is to make them Options:
  A) soluble
  B) biodegradable
  C) cheaper
  D) foamy
  Show Answer
  The correct answer is B .
• Question 1656: The modern process of manufacturing steel for iron is by Options:
  A) treatment with acids
  B) oxidation
  C) blast reduction
  D) treatment with alkanal
  Show Answer
  The correct answer is C .
• Question 1657:

  What is the maximum number of electrons that can occupy the second energy level (n=2)?

  Options:
  A) 2 electrons
  B) 18 electrons
  C) 8 electrons
  D) 32 electrons
  Show Answer
  The correct answer is C .
• Question 1658: Metals of the first transition series have special properties which are different from those of groups I and II elements because they have partially filled Options:
  A) s orbitals
  B) p orbitals
  C) d orbitals
  D) f orbitals
  Show Answer
  The correct answer is C .
• Question 1659: Synthetic rubber is made by polymerization of? Options:
  A) 2 methyl buta - 1, 3 - diene
  B) 2 methyl buta - 1, 2 - diene
  C) 2 methyl but -1-ene
  D) 2 methyl but-2-ene
  Show Answer
  The correct answer is A .
• Question 1660: Water has a rather high boiling point despite its low molecular mass because of the presence of? Options:
  A) hydrogen bonding
  B) covalent bonding
  C) ionic bonding
  D) metallic bonding
  Show Answer
  The correct answer is A .