Question

Which of the following compounds has the highest vapor pressure at 25°C?

A. CH3CH2OH
B. CH3OCH3
C. CH3CH2CH2Cl
D. CH3CH2CH3
E. CH3CH2CH2CH

Answer 1

Generally, increased molar mass increases boiling point and decreases vapor pressure. Therefore, the highest vapor pressure should be due to the molecule with the lowest molar mass.

Answer 2

Also, look at hydrogen bonding if the molar mass is the same or close to the same.