Question

gas can be liquefied easily NH3 or CO2

Answer 1

carbon dioxide is the answer

Answer 2

carbon dioxide gas is easy liquefiable than Ammonia gas this is because compressibility factor for Carbon dioxide is more negative than ammonia. it is further becuz of the reason that in case of carbon dioxide forces of attraction are stronger than in ammonia gas.

so using the concept of real gas equation we can find that ....critical temperature of Co2 is greater than other gases like ammonia so.it can b liquified at higher temp. so is easily liquifiable gas