Polarity is a measure of the difference in electronegativity between two atoms in a bond. The greater the difference in electronegativity, the more polar the bond. Electronegativity is a measure of an atom's ability to attract electrons.
In the carbonyl group, the oxygen atom is more electronegative than the carbon atom. This means that the oxygen atom attracts electrons more strongly than the carbon atom, creating a polar bond. The dipole moment of the carbonyl group is 2.3 D, which is greater than the dipole moment of the alcohol group (1.7 D).
In summary, the carbonyl group is more polar than the alcohol group because the oxygen atom in the carbonyl group is more electronegative than the oxygen atom in the alcohol group.
