One of the many ways in order to solve for the vapor pressure of pure components at a given temperature is through the Antoine's equation which is written below,
P = 10^(A - B/C+T)
where A, B, and C are constants and T is the temperature in °C and P is the vapor pressure in mm Hg.
For hexane,
A = 7.01
B = 1246.33
C = 232.988
Substituting the known values,
P = 10^(7.01 - 1246.33/232.988+25)
P = 151.199 mm Hg
