Given, KH=105atm Pressure, p=5atm Mole fraction of N2 in air, χN2=0.8. Partial pressure of N2, pN2=χN2×p=0.8×5=4atm According to Henry's law, pN2=KHχN2′ χN2′=
4
105
=4×10−5 It means, 1 mole water contains 4×10−5 moles of N2. ∴10 moles of water contains =4×10−5×10 =4×10−4 moles of N2.