Solutions Question 60
Question: A solution is obtained by dissolving 12 g of urea (mol.wt.60) in a litre of water. Another solution is obtained by dissolving 68.4 g of cane sugar (mol.wt. 342) in a litre of water at are the same temperature. The lowering of vapour pressure in the first solution is [CPMT 2001]
Options:
A) Same as that of 2nd solution
B) Nearly one-fifth of the 2nd solution
C) Double that of 2nd solution
D) Nearly five times that of 2nd solution
Show Answer
Answer:
Correct Answer: A
Solution:
We know that in the first solution number of the moles of urea $ =\frac{\text{Mass of urea}}{m.wt.\text{ of urea}}\times \frac{1}{V} $
$ =\frac{12}{60}\times \frac{1}{1}=0.2 $ and In second solution the number of moles of cane sugar $ =\frac{\text{Mass of cane sugar}}{m.wt.\text{ of cane sugar}} $
$ =\frac{68.4}{342}\times \frac{1}{1}=0.2 $ .
