In a 0.2 molal aqueous solution of a weak acid HX the degree of ionization is 0.3. Taking `K_(f)` for water as 1.85, the freezing point of the solution will be nearest to

Options

A. `-0.481^(@)C`
B. `-0.360^(@)C`
C. `-0.260^(@)C`
D. `+0.480^(@)C`

Answer

A

Explanation

`"Given", m=0.2.K_(f)=1.85andalpha=0.3`
`:.i=1+alpha=1.3`
`DeltaT_(f)="molality"xxK_(f)xxi`
`=0.2xx1.85xx1.3=0.481^(@)C`
`:."Freezing point"=-0.481^(@)C`