Answer:
24.895 kJ/mol
Step-by-step explanation:
The expression for Clausius-Clapeyron Equation is shown below as:
Where,
P is the vapor pressure
ΔHvap is the Enthalpy of Vaporization
R is the gas constant (8.314 J /mol K)
c is the constant.
For two situations and phases, the equation becomes:
Given:
= 271.2 mmHg
= 641.8 mmHg
= 241.3 K
= 259.3 K
So,

ΔHvap = 24895.015 J/mol = 24.895 kJ/mol ( 1 J = 0.001 kJ )