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 201:

  Cr₂O$\frac{2-}{7}$ (aq) + H₂O(1)⇌ 2CrO $\frac{2-}{4}$ (aq) + 2H ⁺ (aq)

  What happens to the reaction above when the hydrogen ion concentration is increased?

  Options:
  A) more of the products will be formed
  B) the reaction will not proceed
  C) the equilibrium position will shift to the right
  D) the equilibrium position will shift to the left.
  Show Answer
  The correct answer is D .
• Question 202: Which of the following gases dissolves in water vapour to produce acid rain during rainfall? Options:
  A) Oxygen
  B) Carbon (II) oxide
  C) Nitrogen
  D) Sulphur (IV) oxide
  Show Answer
  The correct answer is D .
• Question 203: Which of these solutions will give a white precipitate with a solution of barium chloride acidified with hydrochloric acid? Options:
  A) Sodium trioxocarbonate (IV)
  B) Sodium tetraoxosulphate (IV)
  C) Sodium trioxosulphate (IV)
  D) Sodium sulphide
  Show Answer
  The correct answer is A .
• Question 204:

  Which of the following is an example of a primary cell?

  Options:
  A) Alkaline battery
  B) Nickel-cadmium battery
  C) Lead-acid battery
  D) Lithium-ion battery
  Show Answer
  The correct answer is A .
• Question 205: Three drops of a 1.0 mol dm^-3 solution of HCl was added to 20 cm³ of a solution of pH6.4. The pH of the resulting solution will be Options:
  A) close to that of pure water
  B) less than 6.4
  C) greater than 6.4
  D) unaltered
  Show Answer
  The correct answer is B .
• Question 206:

  Which type of chemical combination involves the transfer of electrons from one atom to another, resulting in the formation of oppositely charged ions?

  Options:
  A) Ionic bonding
  B) Hydrogen bonding
  C) Covalent bonding
  D) Metallic bonding
  Show Answer
  The correct answer is A .
• Question 207: The substance often use for vulcanization of rubber is Options:
  A) chlorine
  B) hydrogen peroxide
  C) sulphur
  D) tetraoxosulphate (IV) acid
  Show Answer
  The correct answer is C .
• Question 208:

  Which of the following methods is commonly used to remove suspended impurities from water?

  Options:
  A) Fluoridation
  B) Chlorination
  C) Filtration
  D) Distillation
  Show Answer
  The correct answer is C .
• Question 209:

  A solution X, on mixing with AgNO${}_3$ solution gives a white precipitate soluble in aqueous NH${}_3$, a solution Y, when also added to X, also gives a white precipitate which is soluble when heated solutions X and Y respectively contain

  Options:
  A) Al${}^{3+}$, Cl${}^{-}$
  B) Hg${}^{+}$, SO${}_4^{2-}$
  C) Pb${}^{2+}$, Cl${}^{-}$
  D) Ag${}^{+}$, SO${}_4^{2-}$
  Show Answer
  The correct answer is C .
• Question 210: The active reducing agent in the blast furnace for the extraction of iron is? Options:
  A) carbon
  B) limestone
  C) carbon(II)oxide
  D) calcium oxide
  Show Answer
  The correct answer is C .