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 1: In a water body, too much sewage leads to Options:
  A) a decrease in the temperature of the water which cause in death of aquatic animals
  B) an increase in the number of aquatic animals in the water
  C) an increase in the bacterial population which reduces the level of oxygen in the water
  D) a decrease in the bacterial population which increases the level of oxygen in the water
  Show Answer
  The correct answer is C .
• Question 2: The energy value of petrol can be determined by Options:
  A) Bomb calorimeter
  B) Catalytic cracker
  C) Fractionating column
  D) Thermometer
  Show Answer
  The correct answer is C .
• Question 3:

  A solution X on mixing with AgNO₃ solution, gives a white precipitate solution in NH₃. A Solution Y, when added to X, also gives a white precipiate which is soluble on boiling. Solution Y contains?

  Options:
  A) Ag⁺ ion
  B) Pb²⁺ ion
  C) Pb⁴⁺ ion
  D) Zn²⁺ ion
  E) Al³⁺ ion
  Show Answer
  The correct answer is B .
• Question 4: Which of the following would support the conclusion that a solid sample is a mixture? Options:
  A) the solid can be ground to a fine powder
  B) the density of the solid is 2.25 g dm³
  C) the solid has a melting range of 300^oC to 375^oC
  D) the solid absorbs moisture from the atmosphere
  Show Answer
  The correct answer is C .
• Question 5: Which of the following is an acidic salt? Options:
  A) NaHSO₄
  B) Na₂SO₄
  C) CH₃CO₂Na
  D) Na₂S
  Show Answer
  The correct answer is A .
• Question 6:

  The velocity, V of a gas is related to its mass, M by (k = proportionality constant)

  Options:
  A) V = $\frac{k}{M}$
  B) V = $\frac{k}{M^{\frac{1}{2}}}$
  C) V = $k{M}^2$
  D) V = $(\frac{k}{M}{)}^{\frac{1}{2}}$
  Show Answer
  The correct answer is B .
• Question 7: X is a crystalline salt of sodium solution of X in water turns litmus red and produces a gas which turns lime water milky when added to sodium carbonate. With barium chloride solution, X gives hydrochloric acid. X is Options:
  A) Na ₂CO ₃
  B) NaHCO ₃
  C) NaHSO ₄
  D) Na ₂SO ₄
  Show Answer
  The correct answer is C .
• Question 8: If an equilibrium reaction has ∆H < O, the reaction will proceed favorably in the forward reaction at? Options:
  A) low temperatures
  B) high temperatures
  C) all temperatures
  D) all pressures
  Show Answer
  The correct answer is A .
• Question 9: The constituent common to duralumin and alnico is Options:
  A) Co
  B) Mn
  C) Al
  D) Mg
  Show Answer
  The correct answer is C .
• Question 10: Which of the following is NOT used as a raw material in the Solvay process? Options:
  A) Ammonia
  B) Sodium chloride
  C) Calcium trioxocarbonate (IV)
  D) Sodium trioxocarbonate (IV)
  Show Answer
  The correct answer is D .