0.90g of a non-electolyte was dissolved in 87.9 g of benzene. This reised the boiling point of benzene by `0.25^(@)C`. If the molecular mass of the non-electrolyte is 103.0 g `mol^(-1)` , calculate the molal elecation constant for benzene.

Answer

`"2.515 K kg mol"^(-1)`

Explanation

`M_(2)=(1000M_(b)w_(2))/(w_(1)DeltaT_(b))" or "K_(b)=(M_(2)w_(1)DeltaT_(b))/(1000w_(2))=("103 g mol"^(-1)xx87.90g xx0.25K)/("1000 g kg"^(-1)xx0.90g)="2.515 K kg mol"^(-1).`