Solutions Question 399
Question: The relative lowering of vapour pressure of aqueous solution containing a non-volatile solute is 0.0125. The molality of the solution is
Options:
A) 0.70
B) 0.50
C) 0.80
D) 0.40
Show Answer
Answer:
Correct Answer: A
Solution:
$ \frac{p{}^\circ -p}{p{}^\circ }=X_1=0.0125= $ mole fraction of solute
Mole fraction and molarity are related as
$ \frac{1}{X}-1=\frac{1000}{M\times m} $ $ \frac{1}{0.0125}-1=\frac{1000}{18\times m} $ $ m=0.70 $
