Question

In case of the fractional distillation of air, which of the following are correct?

• A. Liquid oxygen is obtained at $-{185}^{o}C$.
• B. Liquid nitrogen is obtained at $-{198}^{o}C$.
• C. Liquid nitrogen is obtained at $-{185}^{o}C$.
• D. Gaseous oxygen is obtained at $-{198}^{o}C$.

Answer 1

Answer: (A), (B)

The correct options are
A

Liquid oxygen is obtained at $-{185}^{o}C$.

B

Liquid nitrogen is obtained at $-{198}^{o}C$.

The boiling point of Nitrogen is lower than the boiling point of oxygen, due to the week Vanderwall force of attraction.

The boiling point of oxygen is $-{183}^{o}C$ so liquid oxygen is obtained at $-{185}^{o}C$.

The boiling point of nitrogen is $-{195.8}^{o}C$, so liquid nitrogen is obtained at $-{198}^{o}C$.