$\begin{array}{1 1}\text{Plot of }x_A\text{ (mole fraction of A in liquid phase) versus }y_A\text{ (mole fraction of A in vapour phase ) is linear}\\\text{Plot of }x_A\text{ versus }y_B\text{ is linear}\\\text{Plot of }1/x_A\text{ versus }1/y_A\text{ is linear}\\\text{Plot of }1/x_A\text{ versus }1/y_B\text{ is linear}\end{array} $