what is meant by liquefaction of gases? can hydrogen be liquefied by compression at the temperature of liquid air?
Liquefaction of gases refers to the process of converting a gas into its liquid state. This is typically achieved by applying pressure and reducing the temperature of the gas.
Now, in the case of hydrogen, it can indeed be liquefied by compression at the temperature of liquid air. However, it's important to note that hydrogen has a very low boiling point (-252.87°C or -423.17°F) and is considered a cryogenic gas. For hydrogen to be liquefied, it needs to be compressed at extremely low temperatures, typically below its boiling point.
The process of liquefying hydrogen involves several steps. First, the gas is compressed to increase its pressure. Then, to lower the temperature of hydrogen, it is often necessary to use a coolant such as liquid nitrogen or liquid helium. The coolant absorbs the heat from the gas, causing its temperature to decrease further. Eventually, if the temperature and pressure conditions are right, the hydrogen gas will condense into a liquid.
So, to summarize, hydrogen can be liquefied by compression at the temperature of liquid air, but it requires very low temperatures and high pressures to achieve this.