Question

Question #4310f

Answer 1

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 `-OH` 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

`CH_3CHO < CH_3CH_2OH < CH_3COOH`