Consider one-dimensional mass transfer in a moving medium that consists of species A and B with ρ = ρ_A + ρ_B = constant. Mark these statements as being True or False.
_____(a) The rates of mass diffusion of species A and B are equal in magnitude and opposite in direction.
_____(b) D_AB = D_BA.
_____(c) During equimolar counter diffusion through a tube, equal numbers of moles of A and B move in opposite directions, and thus a velocity measurement device placed in the tube will read zero.
_____(d) The lid of a tank containing propane gas (which is heavier than air) is left open. If the surrounding air and the propane in the tank are at the same temperature and pressure, no propane will escape the tank and no air will enter.