1. CO2 can be easily liquefied and even solidified because (a) It has weak forces of attraction (b) It has comparatively more force of attraction than other gases (c) It has more intermolecular space (d) It is present in atmosphere.
The intermolecular force of attraction between the particles of carbon dioxide gas is less. So when we are cooling the gas or reduce the pressure of the gas the molecules easily become solid. Thus, the correct option is (a)