Question

The boiling point elevation constant for toulene is 3.32 K Kg/ mol, normal boiling point of toulene is 110.7 degree Celsius. The enthalpy of vaporization of toul ene in would be nearly

Answer 1

Dear Student,
This answer to this question is 34kJ/mol.
molar mass of toluene, M=92.14 g/mol
K_b = 3.32 KKg/mol
T_b = 110.7 °C = 383.7 K
R = 8.314 Nm/K
Boiling point elevation constant is given by-
K_b = MRT_b² / 1000 E_vap
E_vap = MRT_b² / 1000K_b
E_vap = (92.14× 8.314×383.7²) / (1000×3.32)
E_vap= 33.97 kJ/mol

Thus Enthalpy of vaporization of toulene is nearly 34 kJ/mol