Question

For a solution formed by mixing liquids L and M, the vapour pressure of L plotted against the mole fraction of M in solution is shown in the following figure. Here x_L and x_M represent mole fractions of L and M, respectively, in the solution. The correct statement(s) applicable to this system is(are)

(A) Attractive intermolecular interactions between L-L in pure liquid L and M-M in pure liquid M are stronger than those between L-M when mixed in solution 

(B) The point Z represents vapour pressure of pure liquid M and Raoult’s law is obeyed when x_L → 0 

(C) The point Z represents vapour pressure of pure liquid L and Raoult’s law is obeyed when x_L → 1 

(D) The point Z represents vapour pressure of pure liquid M and Raoult’s law is obeyed from x_L = 0 to x_L = 1

Answer 1

(A) Attractive intermolecular interactions between L-L in pure liquid L and M-M in pure liquid M are stronger than those between L-M when mixed in solution 

(C) The point Z represents vapour pressure of pure liquid L and Raoult’s law is obeyed when x_L → 1 

From graph it is clear that there is +ve deviation w.r.t L. Therefore option A is correct. When x_L → 1, then Z will have value equal to \(P^0_L\) (vapour pressure of pure L).