Solutions Question 407
Question: Calculate the weight of non-volatile solute having molecular weight 40, which should be dissolved in 57 g octane to reduce its vapor pressure to 80%:
Options:
A) 47.2 g
B) 5g
C) 106.2g
D) None of these
Show Answer
Answer:
Correct Answer: B
Solution:
$ P_{s}=( \frac{80}{100} )P^{o},w=- $ $ M_{solute}=40,,w=114g,,M_{solvent}=114 $ $ \frac{P_{{}}^{O}-P_{s}}{P_{s}}=\frac{w\times M_{solvent}}{M_{solute}\times W} $ or $ \frac{P_{{}}^{O}-( 80/100 )P^{O}}{( 80/100 )P^{O}}=\frac{w\times 114}{40\times 57} $
$ \therefore $ $ w=5g $
