Mark the Incorrect statement about aldehydes and ketones.
Correct answer: B. They have higher boiling points than that of alcohols.
- A. They have lower boiling points than that of alkalies.
- B. They have higher boiling points than that of alcohols.
- C. They have a lower boiling point than resulting camphor.
- D. Aldehydes have H-bonding but ketones do not have.
Explanation
Explanation:The correct option is B, they have higher boiling points than that of alcohols.Alcohols have strong intermolecular hydrogen bonding, leading to high boiling points. Aldehydes and ketones, which lack O-H bonds, cannot form hydrogen bonds with themselves and rely on weaker dipole-dipole interactions. Therefore, alcohols have higher boiling points than aldehydes/ketones of similar molecular weight.The other options are incorrect because;Option A: They have higher boiling points than that of alkanes. Alkanes are non-polar and only have weak London dispersion forces. Aldehydes and ketones are polar due to the C=O bond and exhibit stronger dipole-dipole interactions. Thus, they have significantly higher boiling points than alkanes of similar molecular weight. This statement is correct.Option C: They have a lower boiling point than that of carboxylic acids.Carboxylic acids (R-COOH) form very strong dimers via two hydrogen bonds. This results in much higher boiling points compared to aldehydes and ketones of similar size. This statement is correct.Option D: Aldehydes have H-bonding but ketones do not have. This statement is misleading. Both aldehydes and ketones cannot form hydrogen bond with themselves because they lack a hydrogen atom directly bonded to a high electronegative atom like oxygen, nitrogen etc. However, they can form hydrogen bond with water molecules, which is why smaller aldehydes and ketones are soluble in water.
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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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