solution

[Solutions]
Solution whether it be gaseous, liquid or solid "is a homogeneous mixture of two or more substances, it is a single phase".
Ideal solution "Raoult s Law"
A measure of the mutual attraction of particles in a liquid is the vapour pressure of that liquid. This is the pressure of the vapour of a substance which is is equilibrium with it s liquid at constant temperature.
Raoult s Law states that the relative lowering of the vapour pressure of a solvent due to the addition of a solute is equal to the molecular fraction of the solute in the solution.

Imagine two substances, A and B, form a solution. Each substance exerts its own vapour pressure, PA and PB respectively, at any particular composition of the solution and the total vapour pressure (P) of the solution is equal to PA +PB. Let P_A^° and P_B^° the vapour exerted by the pure substance A and B, then according to Raoult s Law, if XA and XB are the mole fractions of A and B:
?((P_A^°-P_A)/(P_A^° ))= x_B and ?((P_B^°-P_B)/(P_B^° ))= x_A