The freezing point of a `0.05` molal solution of a non-electrolyte in water is:
(`K_(f) = 1.86 "molality"^(-1)`)

Options

A. `-1.86^(@)C`
B. `-0.93^(@)C`
C. `-0.093^(@)C`
D. `0.93^(@)C`

Answer

C

Explanation

As we know ,the depression in freezing point is
`DeltaT_(f)=K_(f)xx i xx "molarity"`
From question,molal concentration ` = C _(m)=0.05m`
for, non-electrolytes,`i=1 K_(f)=1.86`
`:. DeltaT_(f)=1.86xx1xx0.05=0.0930^(@)C`
hence, F.P.of solution `=0-0.093^(@)C=-0.093^(@)C`