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 831:

  Which of the following reactions is (are) feasible?

  I Br ₍₁₎ + 2CI _2(aq) 2Br _(aq) + CI _2(g)

  Ll 21 _(aq) + Br ₂₍₁₎ 2Br _(aq) + 1 _2(s)

  Lll 2F _(aq) + CI _2(g) 2CI _(aq) + F _2(g) IV 2F _(aq) + Br ₂₍₁₎ 2Br _(aq) + F _2(g)

  Options:
  A) l
  B) ll
  C) l and lll
  D) lll and lV
  Show Answer
  The correct answer is B .
• Question 832:

  A few drop of conc HCL are added to about 10cm${}^3$ of a solution of PH 3.4. The PH of the resulting mixture is?

  Options:
  A) less than 3.4
  B) greater than 3.4
  C) unaltered
  D) the same as that of the pure water
  Show Answer
  The correct answer is A .
• Question 833:

  The enzyme that converts glucose to ethylalcohol is?

  Options:
  A) maltase
  B) zymase
  C) Diatase
  D) Invertase
  Show Answer
  The correct answer is B .
• Question 834: According to Charle's law, the volume of a gas becomes zero at Options:
  A) −100°c
  B) −273°c
  C) −373°c
  D) 0°c
  Show Answer
  The correct answer is B .
• Question 835:

  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 836:

  What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution?

  Options:
  A) 24,125 C
  B) 48,250 C
  C) 72,375 C
  D) 96,500 C
  Show Answer
  The correct answer is B .
• Question 837:

  An aqueous solution of a metal salt, M. gives a white precipitate with NaOH which dissolves in excess NaOH. With aqueous ammonia, the solution of M also gives a white precipitate which dissolves in excess ammonia Therefore the cation in M is

  Options:
  A) Zn
  B) Ca
  C) Al
  D) Po
  Show Answer
  The correct answer is A .
• Question 838:

  A gaseous metallic chloride MCl_x consists of 20.22% of M by mass. The formula of the chloride is

  [M = 27, Cl = 35.5]

  Options:
  A) MCl
  B) MCl₂
  C) MCl₃
  D) M₂Cl₆
  Show Answer
  The correct answer is C .
• Question 839:

  

  The diagram above represents the formation of

  Options:
  A) a metallic bond
  B) an electrovalent bond
  C) a covalent bond
  D) a coordinate covalent bond
  Show Answer
  The correct answer is C .
• Question 840:

  

  Consider the solubility curves of three salts X, Y and Z given in the diagram. If each solution of the salt contains 200 g, and is heated to 100°C, which solution or solutions will deposit 100 g of the solute when suddenly cooled to 0°C?

  Options:
  A) X only
  B) Y only
  C) Z only
  D) X and Z
  E) Y and Z
  Show Answer
  The correct answer is E .