Stoichiometry
According to Raoult's law, "The vapor pressure exerted by component in a solution is proportional to the mole fraction of that component." Raoult's law is not applicable under the following assumption/condition.
The attractive forces between like and unlike molecules are almost equal
No component is concentrated at the surface of the solution
The component molecules are non polar and are of almost equal size
In the formation of solution, chemical combination/molecular association between unlike molecules takes place
EXAMIANS