Question

Explain the method to obtain gases from air.

Answer 1

Air:

1. Air is a homogeneous mixture of gases like nitrogen, oxygen, argon, and other gases.
2. These gases can be separated by using the method of fractional distillation.
3. Initially, the air is liquefied by increasing the pressure followed by lowering the temperature resulting in the formation of liquefied air.
4. Then the liquefied air is warmed slowly in fractional distillation and gases are separated at different times depending on the difference in their boiling points.

• Nitrogen having the lowest boiling point of $-196°\mathrm{C}$ gets distilled first and thus separated out first.
• Followed by nitrogen, argon having a slightly higher boiling point of $-186°\mathrm{C}$ gets separated out after nitrogen.
• Then oxygen having a boiling point of $-183°\mathrm{C}$ is distilled after argon and separated out.

Thus, different gases present in the air are separated.