Solutions Question 400
Question: Vapour pressure of $ CCl_4 $ at $ 25^{o}C $ is 143 mm of Hg. 0.5 gm of a non-volatile solute (mol. wt. = 65) is dissolved in 100 ml $ CCl_4. $ Find the vapour pressure of the solution (Density of $ CCl_4=1.54,g.cm^{3} $ )
Options:
A) 141.93 mm
B) 94.39 mm
C) 199.34 mm
D) 143.99 mm
Show Answer
Answer:
Correct Answer: A
Solution:
$ \frac{P^{o}-P_{S}}{P^{o}}=\frac{w\times M}{m\times W}\Rightarrow p_{s}=p^{o}-p^{o}( \frac{w\times M}{m\times W} ) $ $ =143-\frac{0.5\times 154}{65\times 158}\times 143 $ $ \text{=143-1}\text{.07=141}\text{.93 mm}\text{.} $
