121.

Why the order of boiling of isomeric amines are Primary > Secondary > Tertiary ?

Primary amines and secondary amines are engaged in intermolecular association due to hydrogen bonding between the nitrogen of one and hydrogen of another molecule. This intermolecular association is more in primary amines than in secondary amines as there are two hydrogen atoms available for hydrogen bond formation in it. Tertiary amines do not have intermolecular association due to the absence of hydrogen atom available for hydrogen bond formation. Therefore, the order of boiling points of isomeric amines is as.
Primary > Secondary > Tertiary