On dissolving 2.34g of non-electrolyte solute in 40g of benzene, the boiling point of solution was higher than benzene by 0.81K. Kb value for benzene is 2.53 K `kgmol^(-1)` .Calculate the molar mass of solute. [Molar mass of benzene is 78 `gmol^(-1)`]

Explanation

`M_(2) = (k_(b) xx w_(2) xx 1000)/(Delta T_(b) xx W_(1))`
` = (2.53 xx 2.34 xx 1000)/(0.81 xx 40)`
= `182.72 g " mol"^(-1)`
OR
`Delta T_(b) = K_(b) xx m`
= `K_(b) xx ((w_(2))/(m_(2)))/((w_(1))/(m_(1)))`
`M_(2) = (2.53 xx 2.34 xx 1000)/(0.81 xx 40)`
= 182.7 g `mol^(-1)`