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 451: Ethanol reacts with aqueous sodium mono-oxoio date (l) to give a bright yellow solid with a characteristic smell. The product is? Options:
  A) trichloromethane
  B) triodomethane
  C) iodoethane
  D) ethanal
  Show Answer
  The correct answer is B .
• Question 452: In the preparation of ammonia, which of the following is used as the drying agent? Options:
  A) CaO
  B) CaCI₂
  C) Conc. H₂SO₄
  D) P₂O₅
  E) H₃PO₄
  Show Answer
  The correct answer is A .
• Question 453:

  Which of the following is a physical change?

  Options:
  A) Exposing white phosphorus to air
  B) Burning kerosene
  C) Dissolving calcium in water
  D) Freezing ice cream
  Show Answer
  The correct answer is D .
• Question 454: The uncovered raw food that is sold along major roads is likely to contain some amounts of Options:
  A) Pb
  B) Cu
  C) Ag
  D) Na
  Show Answer
  The correct answer is A .
• Question 455: The nucleus of an atom contains Options:
  A) protons only
  B) neurons only
  C) protons and electrons
  D) neutrons and electrons
  E) protons and neutrons
  Show Answer
  The correct answer is E .
• Question 456:

  Mg²⁺_(aq) + 2e^->_(aq) → Mg_(s)E°_(volts) = 2.370

  Zn²⁺_(aq) + 2e^->_(aq) → Zn_(s)E°_(volts) = -0.763

  Cds²⁺_(aq) + 2e^->_(aq) → Cd_(s)E°_(volts) = 0.403

  Cu²⁺_(aq) + 2e^->_(aq) → Cu_(s)E°_(volts) = 0.340

  In the electrochemical series above, the strongest reducing agents is?

  Options:
  A) Cu _(s)
  B) Cd_(s)
  C) Znsub>(s)
  D) Mg_(s)
  Show Answer
  The correct answer is D .
• Question 457: 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 458: The tincture of iodine means iodine dissolved in Options:
  A) ethanol
  B) bromine chloride
  C) chlorine water
  D) water
  Show Answer
  The correct answer is A .
• Question 459: A given mass of gas occupies 2 dm³ at 300k. At what temperature will its volume be doubled keeping the pressure constant? Options:
  A) 400 k
  B) 480 k
  C) 550 k
  D) 600 k
  Show Answer
  The correct answer is D .
• Question 460: What is the pH of 0.001 mol dm4 solution of sodium hydroxide? Options:
  A) 14
  B) 13
  C) 12
  D) 11
  E) 10
  Show Answer
  The correct answer is D .