1-Pentanol is a polar molecular compound. This is largely due to the presence of a hydroxyl (-OH) group, which is characteristic of alcohols. The oxygen atom in the -OH group is more electronegative than the hydrogen atom, leading to a significant dipole moment. This means that one end of the molecule carries a partial negative charge while the other end carries a partial positive charge, hence making the molecule polar.
In terms of intermolecular forces, 1-pentanol primarily exhibits hydrogen bonding due to the -OH group. Hydrogen bonds are strong attractions that occur between the hydrogen atom of one molecule and the electronegative atom (like oxygen) of another molecule. In addition to hydrogen bonding, 1-pentanol also possesses dipole-dipole interactions because of its polar nature, as well as London dispersion forces, which are present in all molecular compounds regardless of polarity.