$A$ gas can be liquefied:

Explain how liquefaction can occur in different steps within the same phase using an example.

$A$ gas can be liquefied at temperature $T$ and pressure $p$ provided:

The temperature and pressure at which ice,liquid water,and water vapour can exist together are:

An ideal gas cannot be liquefied because ........

Two different gases $A$ and $B$ are filled in separate containers of equal capacity under the same conditions of temperature and pressure. On increasing the pressure slightly,gas $A$ liquefies,but gas $B$ does not liquefy even on applying high pressure until it is cooled. Explain this phenomenon.