Both aldehydes and ketones are planar to the neighborhoods of the carbonyl (C=O) group. Which one of the following bonds is distorted towards the oxygen atoms?
Correct answer: A. π-bond of C and O
- A. π-bond of C and O
- B. Sigma bond of C and H
- C. Sigma bond of C and O
- D. Sigma bond of C and C
Explanation
The correct answer is the π-bond of C and O. In a carbonyl group, the π-bond is formed by the overlap of p-orbitals from carbon and oxygen. Due to the higher electronegativity of oxygen compared to carbon, the shared electron density is pulled towards the oxygen atom, resulting in a distortion of the bond. This distortion is significant because it contributes to the reactivity of aldehydes and ketones.In contrast, the sigma bond of C and H does not experience such distortion since hydrogen is less electronegative than carbon, allowing the bond to remain relatively unaffected. The sigma bond of C and O is also part of the carbonyl but is not distorted in the same manner as the π-bond, as it is a single bond. Lastly, the sigma bond of C and C does not involve oxygen and therefore is not relevant to the question of distortion in the carbonyl group.
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About Aldehydes and Ketones
Aldehydes and ketones contain the polar carbonyl group, but aldehydes are generally more readily oxidised and more reactive than ketones. Coverage includes preparation by oxidation or reduction routes, nucleophilic addition of reagents such as hydrogen cyanide and bisulfite, and tests that distinguish aldehydes from ketones.
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