Calculate the freezing point depression expected for `0.0711` m aqueous solution of `Na_(2)SO_(4)` . If this solution actually freezes at `-0.320 ^(@)C` , what would be the value of Van't Hoff factor ?
(`K_(f)` for water is `1.86 ^(@)C mol^(-1)`) .

Answer

`0.132^(@)C, 2.42`

Explanation

Expected (calculated) `DeltaT_(f)=K_(f)xxm=1.86xx0.0711=0.132^(@)C` (assuming no dissociation)
Actual (observed )`DeltaT_(f)=0.320^(@)C`
`i=((DeltaT_(f))_("obs"))/((DeltaT_(f))_("cal"))=(0.320)/(0.132)=2.42.`