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 2261: Which of these pairs are synthetic and natural macromolecules respectively? Options:
  A) Haemoglobin and nylon, creatine and polyethylene
  B) Nylon and polyethlene, creatine and Haemoglobin
  C) Nylon and creatine, polyethylene and haemoglobin
  D) Polyethylene and creatine, nylon and haemoglobin
  Show Answer
  The correct answer is C .
• Question 2262: wH₂SO₄ + xAI(OH)₃ → yH₂O + = zAI₂(SO₄)₃. The respective values of w.x.y and z in the equation above are? Options:
  A) 2,2,5 and 1
  B) 3,2,5 and 2
  C) 3,2,6 and 1
  D) 2,2,6 and 2
  Show Answer
  The correct answer is C .
• Question 2263: 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 2264: Which of the following reactions does not take place in the smelting of iron in a blast furnace? Options:
  A) CaCO_3(s) CaO_(s) + CO_2(g)
  B) C_(s) + O_2(g) CO_2(g)
  C) 3FeCO_(s) + 2OCO_2(g) FeO_4(s)
  D) SiO_2(s) + CaO_(s) CaCO_3(s)
  E) CO_2(g) + C_(s) 2CO_(g)
  Show Answer
  The correct answer is C .
• Question 2265: S₂O^2-₃ + I₂ → S₂O₆^2- + 2I^-. In reaction above, the oxidizing agent is? Options:
  A) S₂O₃^2-
  B) I₂
  C) S₄O₆^2-
  D) I^-
  Show Answer
  The correct answer is B .
• Question 2266: An oxide XO₂ has a vapour density of 32. What is the atomic mass of X? Options:
  A) 20
  B) 32
  C) 14
  D) 12
  Show Answer
  The correct answer is B .
• Question 2267: Which of the following substances is a basic salt? Options:
  A) Na₂CO₃
  B) Mg(OH)CI
  C) NaHCO₃
  D) KSO₄.AI₂(SO₄)₃,24H₂O
  Show Answer
  The correct answer is B .
• Question 2268: What is discharged at the cathode during the electrolysis of copper (ll) tetraoxosulphate (VI) solution? Options:
  A) Cu ²⁺ only
  B) H + only
  C) Cu ²⁺ and H
  D) Cu ²⁺ and SO ^2-
  Show Answer
  The correct answer is A .
• Question 2269: which of the following polymers is suitable for packaging and electrical insulation? Options:
  A) polyamide
  B) polyethene
  C) polycarbonate
  D) polystyrene
  Show Answer
  The correct answer is D .
• Question 2270: The most important use of hydrogen is in the Options:
  A) manufacture of ammonia
  B) manufacture of methyl alcohol
  C) manufacture of ethyl alcohol
  D) hydrogenation of oils
  Show Answer
  The correct answer is A .