Answer
See the answer below.
Work Step by Step
Number of moles of water vapor:
$375\ g\div 39.948\ g/mol=10.42\ mol$
Van der Waals equation:
$\left[P+a\left(\dfrac nV\right)^2\right](V-bn)=nRT$
$(P+5.82\ atm)×4.66\ L=254.83\ L.atm$
$P=48.8\ atm$
Ideal gas:
$PV=nRT$
$P=50.96\ atm$
The term $bn$ has a slightly bigger influence in this difference.
