Question

`1.0 g` of non-electrolyte solute dissolved in `50.0 g` of benzene lowered the freezing point of benzene by `0.40 K`. The freezing point depression constant of benzene is `5.12 kg mol^(-1)`. Find the molecular mass of the solute.
A. `206 g mol^(-1)`
B. `226 g mol^(-1)`
C. `246 g mol^(-1)`
D. `256 g mol^(-1)`

Answer 1

Correct Answer - D
`DeltaT_(f)=mK_(f)=(w)/(Mw)xx(1000)/(W_(A))xxK_(f)`
`Mw=(1)/(0.4)xx(1000)/(50)xx5.12=256`