The freezing point of of aqueous solution that contains `3%` urea. `7.45% KCl` and `9%` of glucose is (given `K_(f)` of water `=1.86` and asume molarity `=` molality)

Options

A. `290K`
B. `285.5K`
C. `267.42K`
D. `250K`

Answer

C

Explanation

`DeltaT_(f)=i.m.K_(f)`
`DeltaT_(f)=i_(1)m_(1)K_(f)+i_(2)m_(2)K_(f)+i_(3)m_(3)K_(f)=(m_(1)+2m_(2)+m_(3))K_(f)`
`DeltaT_(f)=((3)/(60)+(7.45xx2)/(74.5)+(9)/(180))/(100)xx1000xx1.86`
`DeltaT_(f)=3xx1.86 =5.58`
`T_(f)` of solution `=273-5.58=267.42K`