Are aldehydes and ketones polar?

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Multiple Choice

Are aldehydes and ketones polar?

The carbonyl group in aldehydes and ketones creates polarity because oxygen is highly electronegative and pulls electron density toward itself. This leaves the carbon with a partial positive charge and the oxygen with a partial negative charge, generating a dipole moment. The overall molecule is therefore polar, able to engage in dipole–dipole interactions and to some extent hydrogen-bond accepting with water. It is covalent, not ionic, and while there are nonpolar alkyl parts, the polar carbonyl dominates, so these compounds are not classified as nonpolar or ionic. They aren’t considered amphipathic in the strict sense—the key feature is the polar carbonyl that makes the molecule polar.

The carbonyl group in aldehydes and ketones creates polarity because oxygen is highly electronegative and pulls electron density toward itself. This leaves the carbon with a partial positive charge and the oxygen with a partial negative charge, generating a dipole moment. The overall molecule is therefore polar, able to engage in dipole–dipole interactions and to some extent hydrogen-bond accepting with water. It is covalent, not ionic, and while there are nonpolar alkyl parts, the polar carbonyl dominates, so these compounds are not classified as nonpolar or ionic. They aren’t considered amphipathic in the strict sense—the key feature is the polar carbonyl that makes the molecule polar.

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