4. Air concentrated with solute P is brought in contact with water. At steady state, the bulk concentration of P in air and water are 0.3 and 0.02 respectively. The equilibrium equation relating the interface composition is $$y_{p,i} = 0.25x_{p,i}$$. Assume that the mass transfer co-efficient $$F_G = F_L$$ are identical. The gas phase mole fraction of P at the interface ($$y_{p,i}$$) is