Ice,water,and steam coexist in equilibrium at which of the following conditions?

What are the critical constants?

Which are the most favorable conditions for the liquefaction of a gas?

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

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.

$A$ liquid can exist only,