Question

The boiling point of liquid oxygen is:
A. $-156{}^\circ C$
B. $-196{}^\circ C$
C. $-183{}^\circ C$
D. $-173{}^\circ C$

Answer 1

Hint: Oxygen is the second largest gas of the atmosphere having 20.8% volume existence. The liquid oxygen is pale blue in colour and very cold. It Is non-flammable but a very strong oxidizer. The oxygen can react with all the metals forming their oxides and react very vigorously as a substance which burns in air will readily burn in the presence of oxygen.

Complete Solution :
- Liquid oxygen is a cryogenic liquid. Cryogenic liquids are liquified gases whose normal boiling point is below $-150{}^\circ C$. Therefore, the boiling point of liquid oxygen is $-183{}^\circ C$, because it is very essential to keep the liquid oxygen protected from the surrounding heats even in winters otherwise, it has its own health hazards. The equipment of handling liquid oxygen is also very specific as it is mostly liquified to save the cost of transporting and storing.
- If we look at the storage system of liquid oxygen in brief, then there is a storage system with a cryogenic tank, vaporizers, pressure control system and piping. The construction of a cryogenic tank is similar to an insulated thermos bottle, there are two layers separated from each other with a distance, the outer layer protects the liquid oxygen to be in contact with the surrounding. Vaporizers convert the liquid oxygen into gas and the pressure system maintains the pressure.
So, the correct answer is “Option C”.

Note: There are some serious health hazards related to the liquified oxygen at concentrations more than 80% for a longer period of time, then it can cause irritation in the lungs, nose stiffness and sore throat.