# Question #4310f

Dec 5, 2016

In ethanoic acid dimerisation occurs forming two H-bonds between two molecules making effective molar mass double as shown above.

In ethanol H-bond is also formed as shown above but dimerisation does not occur. So molecular association is less than that of ethanoic acid

In ethanal no $- O H$ group is present. So there exists no H-bond between ethanal molecules.
Here the molecules are associated with less strong dipole-dipole attraction.

So their boiling points are in the following order

$C {H}_{3} C H O < C {H}_{3} C {H}_{2} O H < C {H}_{3} C O O H$