Ideal solutions are binary solutions which follow the Raoult’s Law over the entire range of concentrations, which states that the partial vapour pressure of the components of a solution is directly proportional to its mole fraction in the solution. Also, total vapour pressure over the solution can be related to the mole fraction of any one component. The graphs between the partial vapour pressure for components of an ideal solution should be a straight line.

p1 ∝x1 and p2 ∝x2

From the given figures, the proportion is correctly given by options (i) and (iv). Hence the correct options are (i) and (iv).