Carboxylic acids have higher boiling points than aldehydes, ketones and even alcohols of comparable molecular mass. It is due to their

Question

The number of \(\pi\)-bonds present in benzoic acid is:

Answer 1

To understand why carboxylic acids have higher boiling points compared to aldehydes, ketones, and alcohols of similar molecular masses, we need to consider the nature of the intermolecular forces involved.

Carboxylic acids have the functional group -COOH, which enables the molecules to form strong intermolecular hydrogen bonds with each other. This occurs due to the presence of both a hydrogen atom bonded to an electronegative oxygen atom, and a carbonyl group (C=O) with a lone pair of electrons on the oxygen, allowing for the formation of a hydrogen bond.
The intermolecular hydrogen bonding significantly enhances the boiling point because it requires more energy to break these bonds during the phase transition from liquid to gas.
Other functional groups, such as aldehydes and ketones, do not have hydrogen atoms bonded to oxygen, and therefore cannot form hydrogen bonds as effectively as carboxylic acids. Alcohols can form hydrogen bonds, but not as extensively as carboxylic acids, which often form dimers in the liquid state.
This dimerization is a strong association brought about by two hydrogen bonds per dimer, which requires additional energy to break compared to single hydrogen bonds found in alcohols.

Thus, the correct option is:

formation of intermolecular H-bonding

Other options can be ruled out because:

Formation of intramolecular H-bonding: This would reduce the ability to form intermolecular interactions, thus not significantly increasing the boiling point.
More extensive association via van der Waals force: While van der Waals forces contribute to boiling points, they are weaker compared to hydrogen bonds.
Formation of carboxylate ion: This is a process related to ionization during reactions and does not directly relate to boiling points.

Answer 2

To understand why carboxylic acids have higher boiling points compared to aldehydes, ketones, and alcohols of similar molecular masses, we need to consider the nature of the intermolecular forces involved.

Carboxylic acids have the functional group -COOH, which enables the molecules to form strong intermolecular hydrogen bonds with each other. This occurs due to the presence of both a hydrogen atom bonded to an electronegative oxygen atom, and a carbonyl group (C=O) with a lone pair of electrons on the oxygen, allowing for the formation of a hydrogen bond.
The intermolecular hydrogen bonding significantly enhances the boiling point because it requires more energy to break these bonds during the phase transition from liquid to gas.
Other functional groups, such as aldehydes and ketones, do not have hydrogen atoms bonded to oxygen, and therefore cannot form hydrogen bonds as effectively as carboxylic acids. Alcohols can form hydrogen bonds, but not as extensively as carboxylic acids, which often form dimers in the liquid state.
This dimerization is a strong association brought about by two hydrogen bonds per dimer, which requires additional energy to break compared to single hydrogen bonds found in alcohols.

Thus, the correct option is:

formation of intermolecular H-bonding

Other options can be ruled out because:

Formation of intramolecular H-bonding: This would reduce the ability to form intermolecular interactions, thus not significantly increasing the boiling point.
More extensive association via van der Waals force: While van der Waals forces contribute to boiling points, they are weaker compared to hydrogen bonds.
Formation of carboxylate ion: This is a process related to ionization during reactions and does not directly relate to boiling points.

Carboxylic acids have higher boiling points than aldehydes, ketones and even alcohols of comparable molecular mass. It is due to their

The Correct Option is D

Solution and Explanation

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