50 cm3 of carbon (II) oxide was exploded with 150 cm3 of air containing 20% oxygen by volume. Which of the reactants was in excess?

  • A Carbon (II) oxide
  • B Carbon (IV) oxide
  • C Oxygen
  • D Nitrogen
jamb 2000chemistry

The correct answer is C. Oxygen

2CO + O2 → 2CO2

50cm3 → 25cm3

20% * 150 = 30cm3

30 cm3 is the volume of oxygen available for the reactions. But only 25 cm3 is required; therefore O2 is in excess

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