Question

$\text{P}-\chi$ curve for a non-ideal liquid mixture is given (see figure). Identify the correct $\text{T}-\chi$ curve for the same mixture.

• A.
• B.
• C.
• D.

Answer 1

The correct option is D

Here the $P-\chi$ curve represents the function of total vapour
pressure with respect to the mole fraction of the given non ideal solution, Now we know that the boiling point is the temperature where the total vapour pressure of the solution becomes equal to the atmospheric pressure. The given $T-\chi$ curve starts from $P=600$ mm Hg, reaches a minima and then again ends at $P=800$ mm Hg.
The boiling point vs mole fraction curve will have an inverted curve as higher the vapour pressure lower the temperature required to boil the solution and vice-versa .