0.70 g of an organic compund when dissolved in 32g of acetone produces in an elevation in boiling point of `0.25^(@)C`. Calculate the molecular mass of the organic compound. `(K_(b)" for acetone "=1.72 K kg mol^(-1))`.

Explanation

`M_(B) = (k_(b) xx 1000xx w_(B))/(w_(A) xx Delta T_(b))`
`w_(B) = 4.2 g , w_(A) = 50 g, Delta T_(b) = 1.8 K`
`k_(f) = 1.71 K m^(-1)`
`M_(B) = (1.71 xx 1000 xx 4.2)/(50 xx 1.8)`
`=79.8 g mol^(-1)`