Question

Which of the following should be most volatile?
(I) $C{H}_{3}C{H}_{2}C{H}_{2}N{H}_2$
(II) $(C{H}_3{)}_{3}N$

(IV) $C{H}_{3}C{H}_{2}C{H}_3$

• A. II
• B. IV
• C. I
• D. III

Answer 1

Answer: (B)

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.