Arrange the following in increasing order of boiling points:
${\left({\mathrm{CH}}_3\right)}_3\mathrm{N},{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH},{\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{NH}}_2$

The increasing order of boiling point is C₂H₅OH > C₂H₅NH₂ > (CH₃)₃N. N−H···N hydrogen bond is weaker than an O−H···O hydrogen bond, because the difference in electronegativity between nitrogen and hydrogen (3.0–2.1 = 0.9) is less than that between oxygen and hydrogen (3.5–2.1 = 1.4).

The boiling point order is as follows:
${\left({\mathrm{CH}}_3\right)}_3\mathrm{N}<{\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{NH}}_2<{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}$