F6 chem order of polarity

The descending order of polarity is water, hexanol, ethyl ethanoate and finally propanone.

Among these 4 species, the polarity is caused by either the O-H bonds, the C=O bonds or the C-O bonds. O-H bonds are of higher polarity due to a greater difference in electronegativity between O and H.
Therefore, the polarities of water and hexanol are greater than those of ethyl ethanoate and propanone.

Among water and hexanol, water molecules have a higher polarity because each H2O molecule has 2 O-H bonds but a hexanol molecule has only one, which makes the O atom in H2O more negative than that in hexanol.

Among ethyl ethanoate and propanone, propanone has a lower polarity as it contains only the C=O bond for polarity, but ethyl ethanoate has both C-O bond and C=O bond and they share the same C atom. This make the C atom in the -COO- bond in ethyl ethanoate more positive than that in the C=O bond in propanone.