N-butylamine (I), diethylamine (II) and N,N-dimethyl ethylamine(III) have the same molar mass. The increasing order of their boiling point is:

Options

A. `III lt II lt I`
B. `I lt II lt III`
C. `II lt III lt I`
D. `II lt I lt III`

Answer

A

Explanation

Extent of H-bonding increases as the number of H-atoms on the N-atoms increases and hence boiling points increases in the order:
`3^(@) lt 2^(@) lt 1^(@), i.e., III lt II lt I`