The boiling a point of benzene is 353.23K. When 1.80 g of a non-volatile solute was dissolved in 90 g of benzene, the boiling point is raised to 354.11 K. Calculate the molar mass of the solute. `K_(b)` for benzene is 2.53 K kg `mol^(-1)`.

Explanation

Molar mass of substance can be calculated as .
`M_(B) = (k_(b) xx w_(B) xx 1000)/(Delta T_(b) xx w_(A))`
` k_(b) = 2.53 K Kg mol^(-1) , w_(B) = 1.80 g, w_(A) = 90g`
`Delta T_(b) = 354.11-353.23 = 0.88 K`
`therefore M_(B) = (2.53 xx 1.80 xx 1000)/(90 xx 0.88) = 57.5 g mol^(-1)`