Question

How Total vapour pressure over the solution why is linearly with the mole fraction of component 2 according to roalts law

Answer 1

Raoult's Law is used to determine the vapour pressure of a solution when a solute has been added to it. The law states that this change in vapour pressure of a substance can be determined by the product of the mole fraction of the substance and the vapour pressure of the pure substance.
P_solvent = X_solvent P^o_solvent
At any given temperature for a particular solid or liquid, there is a pressure at which the vapour formed above the substance is in dynamic equilibrium with its liquid or solid form. This is the vapour pressure of the substance at that temperature. At equilibrium, the rate at which the solid or liquid evaporates is equal to the rate that the gas is condensing back to its original form. All solids and liquids have vapour pressure, and this pressure is constant regardless of how much of the substance is present.