Solutions Question 132
Question: If two substances $ A $ and $ B $ have $ P_A^{0}:,P_B^{0}=1,:,2 $ and have mole fraction in solution 1 : 2 then mole fraction of $ A $ in vapours [DPMT 2005]
Options:
A) 0.33
B) 0.25
C) 0.52
D) 0.2
Show Answer
Answer:
Correct Answer: D
Solution:
Relationship between mole fraction of a component in the vapour phase and total vapour pressure of an ideal solution. $ y_{A}=\frac{P_{A}}{P_{total}}=\frac{x_{A}.P_A^{0}}{x_{A}.P_A^{0}+x_{B}.P_B^{0}} $
$ =\frac{1\times 1}{1\times 1+2\times 2}=\frac{1}{1+4}=\frac{1}{5}=0.2 $
