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 751: The leachate of a certain plant ash is used in local soap making because it contains Options:
  A) sodium chloride and potassium hydroxide
  B) sodium hydroxide
  C) potassium hydroxide
  D) soluble carbonates and hydrogen carbonates
  Show Answer
  The correct answer is B .
• Question 752: Which of the following substances are all made by the process of polymerization? Options:
  A) Nylon and soap
  B) Ethanoic acid margarine and ethanol
  C) Nylon and artificial rubber
  D) Soap and butane
  E) Margarine and nylon
  Show Answer
  The correct answer is C .
• Question 753:

  

  The compound above is the product of the oxidation of

  Options:
  A) 2-methlbutan-2-ol
  B) 2-methylbutan -1- ol
  C) 2, 3-dimethylprop 1-ol
  D) Pentan -2- ol
  Show Answer
  The correct answer is B .
• Question 754:

  An element X has two isotopes, ²⁰₁₀X and ²⁰₁₀X, present in the ratio 1:3. The relative atomic mass of X would be?

  Options:
  A) 20.5
  B) 21.0
  C) 21.5
  D) 22.0
  E) 22.5
  Show Answer
  The correct answer is C .
• Question 755: The density of a certain gas is 1.98gdm^-3 at s.t.p. What is the molecular mas of the gas? Options:
  A) 44.0 g
  B) 54.0 g
  C) 26.0 g
  D) 31.0 g
  Show Answer
  The correct answer is A .
• Question 756: Elements P, Q, R, S have 6, 11, 15, 17 electrons respectively, therefore, Options:
  A) P will form an electrovalent bond with R
  B) Q will form a covalent bond with S
  C) R will form an electrovalent bond with S
  D) Q will form an electrovalent bond with S
  E) Q will form a covalent bond with R
  Show Answer
  The correct answer is D .
• Question 757: Which of the following is a deliquescent compound? Options:
  A) Na₂CO₃
  B) CaCl₂
  C) CuO
  D) Na₂CO₃.10H₂O
  Show Answer
  The correct answer is B .
• Question 758: In which of the following reactions can the oxidation number of the nitrogen be said to have increased? Options:
  A) 2NO_(g) + O_2(g) → 2NO_2(g)
  B) NO_(g) + Cl_2(g) → NOCl_2(l)
  C) FeSO_4(aq) + NO_(g) → Fe(NO)SO_4(s)
  D) NO_(g) + Br_2(l) → NOBr_2(l)
  Show Answer
  The correct answer is A .
• Question 759: In the manufacture of iron in the blast furnace, iron (lll) oxide is mixed with coke and limestone, and different reactions occur in the process. Which of the following statements is true with respect to these reactions? Options:
  A) the coke is a powerful reducing agent and easily converts the iron oxide to iron
  B) the calcuim carbonate reacts with SiO₂ an earthly impurity in the ore, to from calcuim silicate
  C) the coke will react with the iron produced to form steel
  D) all the carbondioxide required in the process comes from the decomposition of the calcium carbonate
  E) the calcium carbonate decomposes to give calcium oxide, which then forms calcium silicate with the earthly impurity
  Show Answer
  The correct answer is E .
• Question 760:

  Which of the following alkanes has a straight-chain structure?

  Options:
  A) Cyclopentane (C5H10)
  B) Isobutane (C4H10)
  C) 2 - methyl propane (C4H10)
  D) Pentane (C5H12)
  Show Answer
  The correct answer is D .