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 71:

  Hydrocarbons which will react with Tollen's reagent conform to the general formula

  Options:
  A) C${}_n$H${}_{2n}$
  B) C${}_n$H${}_{2n+2}$
  C) C${}_n$H${}_{2n-2}$
  D) C${}_n$H${}_{2n+1}$OH
  Show Answer
  The correct answer is C .
• Question 72: An aqueous solution of an inorganic salt gave white precipitate (i) soluble in excess aqueous NaOH (ii) insoluble in excess aqueous NH₃ (iii) with dilute HCl. The cation present in the inorganic salt is? Options:
  A) Na₄⁺
  B) Ca⁺⁺
  C) Zn⁺⁺
  D) Al⁺⁺⁺
  E) Pb₊₊
  Show Answer
  The correct answer is E .
• Question 73: In which order are the following salts sensitive to light? Options:
  A) Agl > AgCl > AgBr
  B) AgCl > Agl > AgBr
  C) AgBr > AgCl > Agl
  D) AgCl > AgBr > Agl
  Show Answer
  The correct answer is D .
• Question 74:

  32g of anhydrous copper(ii)tetraoxosulphate(vi) dissolved in 1dm${}^3$ of water generated 13.0kj of heat. The heat solution is?

  Options:
  A) 26.0kj/mol
  B) 65.0kj/mol
  C) 130.0kj/mol
  D) 260.0kj/mol
  Show Answer
  The correct answer is B .
• Question 75: The oxidation number of manganese in KMnO₄ is? Options:
  A) +1
  B) +3
  C) +5
  D) +7
  E) +2
  Show Answer
  The correct answer is D .
• Question 76: Alkanals can be distinguished from alkanones by the reaction with Options:
  A) sudan lll stain
  B) starch iodide paper
  C) lithium tetrahydrido aluminate (lll)
  D) fehling's solution
  Show Answer
  The correct answer is D .
• Question 77: Two metallic ions associated with hard water are Options:
  A) copper and zinc
  B) magnesium and silver
  C) calcium and magnesium
  D) potassium and tin
  E) sodium and lead
  Show Answer
  The correct answer is C .
• Question 78:

  Which of the following gases will diffuse fastest when passed through a porous plug?

  [H = 1, C = 12, N = 14, O = 16]

  Options:
  A) Propane
  B) Oxygen
  C) Methane
  D) Ammonia
  Show Answer
  The correct answer is C .
• Question 79: Smog usually occurs over cities which Options:
  A) burn a lot of fossil fuels
  B) have very few plants
  C) are surrounded by water
  D) are overpopulated
  Show Answer
  The correct answer is A .
• Question 80: The general formula of an alkyl halide (where X represents the halide) is? Options:
  A) C_nH_2n2X
  B) C_nH_2n + ₁X
  C) C_nH_2n + ₂X
  D) C_nH_2nX
  Show Answer
  The correct answer is B .