The van der Waals constants of four gases are: W ($a=0.034$, $b=0.0237$), X ($a=1.39$, $b=0.0391$), Y ($a=3.59$, $b=0.0427$), Z ($a=4.17$, $b=0.0371$), with $a$ in ${\mathrm{L}}^2\mathrm{atm}\mathrm{mo}{\mathrm{l}}^{-2}$ and $b$ in $\mathrm{L}\mathrm{mo}{\mathrm{l}}^{-1}$. Which statements are correct?

1. AZ is the most easily liquefied gas
2. BY has the largest molecular size among the four
3. CW is likely to show $Z$ greater than 1 at all pressures at room temperature
4. DX has a higher Boyle temperature than Y