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 291: Liquid X, reacts with sodium trioxocarbonate (IV) (Na₂CO₃) to give a gas which turns calcium chloride solution milky X is Options:
  A) Na₂SO₄(aq)
  B) Kl (aq)
  C) an alkali
  D) an acid
  E) a hydrocarbon
  Show Answer
  The correct answer is D .
• Question 292: The salt that reacts with dilute hydrochloric acid to produce a pungent smelling gas which decolourizes acidified purple potassium tetraoxomanganate (VII) solution is Options:
  A) Na₂SO₄
  B) Na₂SO₃
  C) Na₂S
  D) Na₂CO₃
  Show Answer
  The correct answer is B .
• Question 293:

  Which of the following types of bonding does not involve the formation of new substances?

  Options:
  A) Metallic
  B) Covalent
  C) Co-ordinate
  D) Electrovalent
  Show Answer
  The correct answer is A .
• Question 294: 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 295: What volume of oxygen will remain after reacting 8cm³ of hydrogen with 20cm³ of oxygen? Options:
  A) 10 cm³
  B) 12 cm³
  C) 14 cm³
  D) 16 cm³
  Show Answer
  The correct answer is D .
• Question 296: Which of the following gases is the most dangerous pollutant? Options:
  A) Hydrogen sulphide
  B) Carbon (lV) oxide
  C) Sulphur (lV) oxide
  D) Carbon (ll) oxide
  Show Answer
  The correct answer is D .
• Question 297:

  

  Select the right answer from the structure above.Which of the following compounds represents the polymerization product of ethyne?

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is A .
• Question 298:

  

  The appropriate test paper to use in the above experiment is moist

  Options:
  A) litmus psper
  B) potassium heptaoxodichromate (IV) paper
  C) lead (ll) trioxonitrate (V) paper
  D) universal indicator paper
  Show Answer
  The correct answer is C .
• Question 299: Which of the following typically represents a photochemical reaction? Options:
  A) Formation of water from hydrogen and oxygen molecules
  B) Conversion of dinitrogen (IV) oxide to nitrogen (IV) oxide
  C) Decomposition of calcium hydroxide to its oxide
  D) Conversion of silver halides to grey metallic silver
  Show Answer
  The correct answer is D .
• Question 300: The process that requires the use of hardwater in its operation is Options:
  A) Tanning
  B) Bottling
  C) Laundry
  D) Dyeing
  Show Answer
  The correct answer is B .