Calculate the vapor pressure at 25 ? c of hexane above the solution. the vapor pressure of pure hexane at 25 ? c is 151 torr.

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

Which of the following did you identify correctly

The total number of electrons is 14