In water saturated air, mole fraction of water vapour is 0.04. If the total pressure of saturated air is 1.5 atmospheres, the partial pressure of dry air would be

$$\begin{gathered} \mathrm{Mole} \mathrm{fraction} \mathrm{dry} \mathrm{air} + \mathrm{Mole} \mathrm{fraction} \mathrm{of} \mathrm{water} \mathrm{vapour}=1 \\ \mathrm{Mole} \mathrm{fraction} \mathrm{dry} \mathrm{air} = 1- \mathrm{Mole} \mathrm{fraction} \mathrm{of} \mathrm{water} \mathrm{vapour} \\ \mathrm{Mole} \mathrm{fraction} \mathrm{dry} \mathrm{air} = 1- 0.04 \\ \mathrm{Mole} \mathrm{fraction} \mathrm{dry} \mathrm{air} = 0.96 \\ \mathrm{Partial} \mathrm{pressure} \mathrm{of} \mathrm{dry} \mathrm{air} = \mathrm{Mole} \mathrm{fraction} \mathrm{dry} \mathrm{air} \times \mathrm{Total} \mathrm{pressure} \\ \mathrm{Partial} \mathrm{pressure} \mathrm{of} \mathrm{dry} \mathrm{air} = 0.96 \times 1.5 \mathrm{atm} \\ \mathrm{Partial} \mathrm{pressure} \mathrm{of} \mathrm{dry} \mathrm{air} = 1.44 \mathrm{atm} ; \end{gathered}$$