Solutions Question 174
Question: Vapour pressure of solution containing 2 mol of liquid $ A(P_A^{0}=80torr) $ and 3 mol of liquid $ B(P_B^{0}=100torr) $ is 87 torr. We can conclude that
Options:
A) there is negative deviation from Raoult’s law
B) boiling point is higher than that expected for ideal solution
C) molecular attractions between unlike molecules are stronger than those between like molecules
D) All of these statements are correct
Show Answer
Answer:
Correct Answer: A
Solution:
For ideal solution vapour pressure of solution $ =P_A^{{}^\circ }X_{A}+P_B^{{}^\circ }X_{B} $
$ =80\times \frac{2}{5}+100\times \frac{3}{5}=92,torr $ Since observed vapour pressure of solution < ideal vapour pressure, the solution shows negative deviation.
BETA
