Question

It is possible to obtain oxygen from air by fractional distillation because

• A. oxygen is in a different group of the periodic table from nitrogen
• B. oxygen is more reactive than nitrogen
• C. oxygen has higher boiling point than nitrogen
• D. oxygen has a lower density than nitrogen

Answer 1

The Correct Option is C

To understand why oxygen can be obtained from air by fractional distillation, let's explore the characteristics of oxygen and nitrogen related to their physical properties, specifically their boiling points.

1. Boiling Points of Oxygen and Nitrogen:
   • Oxygen boils at approximately -183^{\circ}C.
   • Nitrogen boils at a lower temperature of about -196^{\circ}C.
2. Principle of Fractional Distillation:
   • Fractional distillation is a process used to separate components of a mixture based on differences in boiling points.
   • If two substances are mixed, the one with the lower boiling point will evaporate first when the mixture is heated.
3. Application to Air Separation:
   • In the case of air, which is primarily composed of nitrogen and oxygen, fractional distillation is used to separate these gases by cooling the air until it liquefies, and then slowly warming it.
   • Since nitrogen has a lower boiling point than oxygen, it vaporizes first, leaving behind a liquid rich in oxygen.
4. Conclusion:
   • The correct answer is that "oxygen has a higher boiling point than nitrogen." This property allows oxygen to be separated from nitrogen in air through fractional distillation.