Vapor pressure is inversely proportional to boiling point. The low the boiling point, the compound will have higher vapor pressure.
1. CH₃OH exhibits low boiling point in comparison to CH₃CH₂CH₂OH that exhibits high boiling point. So, CH₃OH has high vapor pressure.
2. CH₃OH is polar and exhibits high boiling point because of hydrogen bonds, in comparison H₂CO exhibits low boiling point and has no hydrogen bonds. So, H₂CO has high vapor pressure.
3. CH₄ is non-polar and exhibits less boiling point in comparison to CH₃Cl, which is polar and exhibits high boiling point. So, CH₄ has high vapor pressure.