The various conditions required for the liquefaction of gases A, B, C and D are given below:

Explanation

Among A, B, C and D gases, D is the most easily liquefiable gas since the temperature required is the highest and pressure required is the lowest. The easier liquefaction indicates greater intermolecular forces of attraction and hence larger deviation from ideal behaviour. The order of ease of liquefaction is `D gt C gt B gt A`, thus the ascending order of extent of deviation from ideal behaviour could be `A lt B lt C lt D`.