A solution is obtained by dissolving `12g`of urea(mol.wt.60)in a litre of water.Another solution is obtained by dissolving `68.4g` 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

Options

A. same as that of `2^(nd)`solution
B. Nearly one-fifth of the `2^(nd)`solution
C. Double that of `2^(nd)`solution
D. Nearly five times that of `2^(nd)`solution

Answer

A

Explanation

We know that in the first solution number of the moles of urea
`("Mass of urea")/("m.wt.of urea")xx(1)/(V)=(12)/(60)xx(1)/(1)=0.2` and,
In second solution the number of moles of cane sugar
`= ("Mass of cane sugar")/("m.wt.of cane sugar")=(68.4)/(342)xx(1)/(1)=0.2`