According to Henry's law,
xN2×KH=pN2
(pN2=Partial pressure of N2)
Given,
Total pressure =5 atm
Mole fraction of N2=0.8
∴ Partial pressure of N2=0.8×5=4⇒xN2×1×105=4⇒xN2=4×10−5Number of moles of H2O,nH2O=10Number of moles of N2,nN2=?nN2nN2+nH2O=xN2=4×10−5nN210+nH2O=xN2=4×10−5⇒nN2=4×10−4Hence,xy=44=1