Depression in `f.p.` of an aqueous urea solutio is `1.86^(@) .(K_(f)=1.86^(@) mol^(-1) kg)` Hence, mole`-` fraction of urea in this soluiton is `:

Options

A. `0.982`
B. `0.567`
C. `0.943`
D. `0.018`

Answer

4

Explanation

As `DeltaT_(f)=` molality `xxK_(f)`
`1.86=mxx1.86`
molality `=1 mol kg^(-1)`
`:. " "` urea `=1 mol`
moles of water `=(1000)/(18)=55.55`
mole fraction of urea `=(1)/(55.55)=0.018`