Figure explains elevation in boiling point when a non-volatile solute is added to a solvent. Provide a thermodynamic explanation of the elevation in boiling point.

Answer

At the boiling point liquid and vapour pase are in equilibrium.
`therefore DeltaG=0`
Also `DeltaG=DeltaH-TDeltaS`
`therefore T=(DeltaH)/(DeltaS)`
If we compare the heats of vaporisation `(DeltaH)~ for a pure solvent and for a solution, we find that the two values are simi9lar because similar intermolecular forces between solvent molecule must be overcome in both cases. In comparing the entropies of vaporisation however, the two values are not similar. because a solution has more molecular randomness than a pure solvent has, the entropy change between solution and vapour is smaller than the entropy change betweeen pure solvent and vapour. Thus, `T` (boiling of solution) must be higher than that of pure solvent
`(##RES_PHY_CHM_V01_XII_C02_E01_303_A01##)`