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 441:

  6AgNO_4(aq) + PH_3(g) + 3H₂O_(l) → 6Ag_(s) + H₃PO_3(g) + 6HNO_3(aq)

  In the above reaction, the reducing agent is

  Options:
  A) HNO_3(aq)
  B) H₂O_(l)
  C) PH_3(g)
  D) AgNO_3(aq)
  Show Answer
  The correct answer is C .
• Question 442:

  At S. T. P how many litres of hydrogen can be obtained from the reaction of 500 cm³ of 0.5 M H ₂SO ₄ with excess zinc metal?

  (Gram molecular volume of H₂ = 22. 4 dm ³)

  Options:
  A) 22.4 dm ³
  B) 11 . 2 dm ³
  C) 6. 5 dm ³
  D) 5. 6 dm ³
  E) 0. 00 dm ³
  Show Answer
  The correct answer is D .
• Question 443: The gaseous pollutant sulphur (IV)oxide is most likely to be detected in fairly reasonable quantities in the area around a plant for the Options:
  A) extraction of aluminium from bauxite
  B) production of margarine
  C) smelting of copper
  D) production of chlorine from brine
  Show Answer
  The correct answer is C .
• Question 444:

  Which of the following is used to power steam engines?

  Options:
  A) lubricating oil
  B) coal
  C) bitumen
  D) diesel oil
  Show Answer
  The correct answer is B .
• Question 445: The air pollutant unknown in nature is Options:
  A) NO
  B) CO
  C) HCHO
  D) DDT
  Show Answer
  The correct answer is C .
• Question 446: The formula CH₂ for ethanoic acid is regarded as its Options:
  A) Molecular formula
  B) General formula
  C) Empirical formula
  D) Structural formula
  Show Answer
  The correct answer is C .
• Question 447:

  Which of the following changes is physical?

  Options:
  A) Adding iron filing to aerated water
  B) Adding sodium metal to water
  C) Cooling a solution of Iron (II) sulphate to obtain the hydrated salt
  D) Cooling water to obtain ice
  E) Burning the domestic gas (Utilgas) for cooking
  Show Answer
  The correct answer is D .
• Question 448: Which of the following compounds is a base? Options:
  A) CO₂
  B) CaO
  C) H₃PO₃
  D) CH₃COOCH₃
  Show Answer
  The correct answer is B .
• Question 449:

  Which of the following are chemical changes?

  I. cooking of food
  II. digestion of food
  III. freezing of water
  IV. water is heated up

  Options:
  A) I and II
  B) I, II, and III
  C) III and IV
  D) all of the above
  Show Answer
  The correct answer is A .
• Question 450: Copper (II) tetraoxosulphate (IV) is widely used as a? Options:
  A) fertilizer
  B) fungicide
  C) disinfectant
  D) purifier
  Show Answer
  The correct answer is B .