Now for compound A when we go from here to here along the x axis the mole fraction increases. For compound B, when we go from here to here on the x axis the mole fraction decreases. The brown line represents the pressure. It's the slope for compound A and the green line represents the pressure of the slope for compound B. Now, as we go as we increase the mole concentration in compound one or compound A, the pressure of it increases. And as we go this way, the mole fraction of this guy compound B decreases.