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 21:

  The contact process is used for the industrial production of

  Options:
  A) sulfuric acid (H2SO4)
  B) Hydrochloric acid (HCl)
  C) Sodium hydroxide (NaOH)
  D) Calcium oxide (CaO)
  Show Answer
  The correct answer is A .
• Question 22:

  If 1 litre of 2.2M sulphuric acid is poured into a bucket containing 10 litre of water,and resulting solution mixed thoroughly, the resulting sulpuric acid concentration will be?

  Options:
  A) 2.2 M
  B) 1.1 M
  C) O.22 M
  D) 0. 11 M
  E) 0.20 M
  Show Answer
  The correct answer is C .
• Question 23: 2CL^-_(aq) → CI_2(g) + 2e^-(aq). The above half-cell reaction occuring at the anode during the electrolysis of dilute ZnCI₂ solution is? Options:
  A) ionization
  B) oxidation
  C) reduction
  D) recombination
  Show Answer
  The correct answer is B .
• Question 24: 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 25: When ΔH is negative, a reaction is said to be Options:
  A) ionic
  B) reversible
  C) exothermic
  D) endothermic
  Show Answer
  The correct answer is C .
• Question 26: The mass of silver deposited when a current of 10A is passed through a solution of silver salt for 4830s is – (Ag = 108 F = 96500(mol^-1) Options:
  A) 54.0g
  B) 27.0g
  C) 13.5g
  D) 108.0g
  Show Answer
  The correct answer is A .
• Question 27: What is the percentage of sulphur in sulphur (IV) oxide? Options:
  A) 66%
  B) 25%
  C) 40%
  D) 50%
  Show Answer
  The correct answer is D .
• Question 28: Iron is often galvanized in order to Options:
  A) make it more malleable
  B) remove the impurities in it
  C) protect it against corrosion
  D) render it passive
  Show Answer
  The correct answer is C .
• Question 29: The repeating unit in natural rubber is Options:
  A) alkyne
  B) isoprene
  C) n-propene
  D) peoprene
  Show Answer
  The correct answer is B .
• Question 30: 28.8 cm³ of nitrogen at 15°C is cooled to O°C at constant pressure, the new volume of nitrogen is? Options:
  A) 17.4 cm³
  B) 14.7 cm³
  C) 27.3 cm³
  D) 31.7 cm³
  Show Answer
  The correct answer is C .