Discussion Forum



1)

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

 

1232020496_graphChem.JPG


A) The point Z represents vapour pressure of pure liquid M and Raoult's law is obeyed from $X_{L}$=0 AND $X_{L}$=1

B) 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 vapor pressure of pure liquid M and raoult's law is obeyed when $X_{L}$$\rightarrow$ 0

D) The point Z represents vapor pressure of pure liquid L and Raoult's law is obeyed when $X_{L}$$\rightarrow$ 1

Answer:

Option B,D

Explanation:

The graph shown indicates that there is a positive deviation because the observed vapor pressure of L is greater than the ideal pressure.

1122020340_ideal pressure.JPG

Since, the deviation is positive, the intermolecular force between L and M is smaller than the same in pure L and pure M.

   Also as XL→ 1, XM → 0. The real curve approaching the ideal curve where Raoult's law will be obeyed.