Question

Which of the following should be most volatile? (I) $CH_3CH_2CH_2NH_2$ (II) $(CH_3)_3N$ (IV) $CH_3CH_2CH_3$

• A. II
• B. IV
• C. I
• D. III

Answer 1

Answer: (B)

IV

Answer 2

The order of boiling points of isomeric amines is $1^?$ amines $>\, 2^?$ amines $> \,3^?$ amines. Because of absence of H-atom available for hydrogen bonding, $3^?$ amines do not have intermolecular association. Intermolecular association is more in $1^?$ amines than in $2^?$ amines as there are two $H$-atoms available for $H$-bonding. Hydrocarbons are almost non-polar molecules and possess weak van der Waals forces and hence has lowest boiling point i.e., most volatile.