Simply put , Raoult 's law states that the vapor pressure , of a binary solution , containing a non-volatile solute , is directly related to the mole fraction of solvent ( i.e. volatile ) in the solution . Established by FranÃ ois-Marie Raoult in 1882 , Raoult 's law states : the vapor pressure of an ideal solution is dependent on the vapor pressure of each chemical component and the mole fraction of the component present in the solution .