The plot of total vapour pressure as a function of mole fraction of the component of an ideal solution formed by mixing liquids X and Y is

When a liquid is completely miscible with another liquid, a homogeneous solution consisting of a single phase is formed. If such a solution is placed in a closed evacuated vessel, the total pressure exerted by the vapour, after the system attained equilibrium will be equal to the sum of partial pressures of the constituents. A solution is said to be ideal if its constituents follow Raoult's law under all conditions of concentrations, i.e., where p_(i) is the partial pressures of the constituent i, whose mole fraction in the solution is x_(i) and p_(i)^(@) is the corresponding vapour pressure of the pure constituent. The change in the thermodynamic functions when an ideal solution is formed by mixing pure components is given by the following expression. Delta_(mix) = G = n_("total") RT sum_(i) x_(i) In x_(i) ...(i) where, n_("total") is the total amount of all the constituents present in the solution. Delta_(mix)F =- n_("total") R sum_(i) x_(i) In x_(i) ......(ii) Delta_(mix)H =- n_("total") RT sum_(i) x_(i) In x_(i) - n_("total") R sum_(i) x_(i) In x_(i) = 0 ........(iii) Delta_(mix) U = 0 .........(iv) Since botli the components of an ideal binary system follow Raoult's law of the entire range of the compositions, the partial pressure exerted by the vapours of these constituents over the solution will be given by p_(A) = x_(A) p_(A)^(@) ..........(v) p_(B) = x_(B) p_(B)^(@) .........(vi) where, x_(A) and x_(B) are the mole fractions of the two constituents in the liquid phase and p_(A)^(@) and p_(B)^(@) are the respective vapour pressure of the pure constituents. The total pressure (p) over the solution will be the sum of the partial pressure. The composition of the vapour phase (y_(A)) can be determined with the help of Dalton's law of partial pressures. Two liquids A and B form an ideal solution at temperature T. when the total vapour pressure above the solution is 600 torr, the mole fraction of A in the vapour phase is 0.35 and in the liquid phase 0.70. The vapour pressure of pure B and A are:

P_1 and P_2 are the vapour pressures of pure liquid components , 1 and 2 respectively of an ideal binary solution if x_1 represents the mole Traction of component 1, and the total pressure of the solutions formed by 1 and 2 will be

Vapour pessure of a liquid or a solution is the pressure exerted by the vapour in equilibrium with the liquid or solution at a particular temperature. It depends upon the nature of the liquid and temperature. It depends upon the nature of the liquid and temperature. According to Raoult's law in a solution, the vapour pressure of a component at a given temperature is equal to the mole fraction of that component in solution multiplied by the vapour pressure of that component in hte pue state. this solution in which each component obeys Raoult's law are called ideal solutions. there are two types of non ideal solutions, showing positive deviations and negative deviations from ideal behaviour. If liquid A and B form ideal solution, then

The vapour pressure of two liquids X and Y are 80 and 60 Torr respectively. The total vapour pressure of the ideal solutions obtained by mixing 3 moles of X and 2 moles of Y would be