Solutions Question 345
Question: 12 g of a nonvolatile solute dissolved in 108 g of water produces the relative lowering of vapour pressure of 0.1. The molecular mass of the solute is:
Options:
A) 80
B) 60
C) 20
D) 40
Show Answer
Answer:
Correct Answer: C
Solution:
$ \frac{P{}^\circ -P_{s}}{P{}^\circ }=\frac{n}{N}=\frac{w}{m}\times \frac{M}{W} $
$ 0.1=\frac{12}{m}\times \frac{18}{108} $
$ m=\frac{12\times 18}{0.1\times 108}=20 $
