ln (k2/k1) = (delta H/R)(1/T1 - 1/T2)
You will need to look up delta H. I dont have those numbers at my finger tips. Post your work if you get stuck.
k1 and k2 are the vapor pressures @ T1 and T2
T1 will be 80.1 C. T2 is the unknown. k1 is the vapor pressure at T1 which is 760 torr. k2 is the vapor pressure of the problem or 440 torr.
At what temperature does benzene boil when the external pressure is 440 torr ?
1 answer