[Q] 4 gases A,B,C and D have compressibility factor 1.6,0.8,0.6 and 1.8 respectively. Arrange them in:
1) Increasing order of their ideal behaviour.
2) Increasing order of their attractive force.

Dear student 

1) Increasing order of their ideal behaviour is  (C) =(D) < (A)= (B) as Z(compressibility factor)=1 is an ideal gas 
2) Increasing order of their attractive force is D<A<B<C.because repulsion decreases volume decrease and hence attraction increase at Z<1

Regards