Tertiary amines lack intermolecular association as they do not have hydrogen atoms available for hydrogen bond formation. Consequently, the order of boiling points among isomeric amines is Primary > Secondary > Tertiary.

Intermolecular association in primary and secondary amines is due to hydrogen bonding between the nitrogen of one molecule and the hydrogen of another. Primary amines exhibit stronger association because they have two hydrogen atoms available for hydrogen bond formation.

Butan-1-ol is expected to be more soluble in water than butan-1-amine because alcohols form stronger intermolecular hydrogen bonds with water compared to amines.

Amines and alcohols with nitrogen and oxygen having electronegativities of 3.0 and 3.5, respectively, exhibit different solubility patterns in water, with alcohols generally being more soluble.

Lower aliphatic amines are soluble in water due to the ability to form hydrogen bonds with water molecules. However, solubility decreases with increasing molar mass of amines because of the larger hydrophobic alkyl part.