Answer the following questions based on the P – T phase diagram of `CO_(2)`:
(a) `CO_(2)` at 1 atm pressure and temperature` – 60^(@)C` is compressed isothermally. Does it go through a liquid phase ?
(b) What happens when `CO_(2)` at 4 atm pressure is cooled from room temperature at constant pressure ?
(c) Describe qualitatively the changes in a given mass of solid `CO_(2)` at 10 atm pressure and temperature `–65^(@)C` as it is heated up to room temperature at constant pressure.
(d) `CO_(2)` is heated to a temperature `70^(@)C` and compressed isothermally. What changes in its properties do you expect to observe ?

Explanation

It will not exhibit any clear transition to the liquid phase, but will depart more and more from ideal gas behaviour as its pressure increases.