Question

Rationalize the following boiling points:

Short answer

Acetic acid has a higher boiling point based on molecular weight and lower surface tension due to its higher polarity related to the water. It has high hydrogen bonding. Because of a higher intermolecular force, it has a high boiling point.

An inductive effect is present in chloroacetic acid because of the chlorine atom. The electron density is reduced over the already weakened O-H bond in the carboxylic moiety, making it a stronger acid. It has a higher boiling point due to the inductive effect and strong intermolecular interactions.

The acetate ester is a polar compound.

But it has no hydrogen atom, which will attach directly to an oxygen atom in the molecules. That's why acetate ester molecules cannot form intermolecular hydrogen bonding with another molecule and thus have considerably lower boiling points.

Step-by-step solution

Boiling point

The boiling point is the temperature of the substance at which the vapor pressure of the liquid equals the pressure surrounding the liquid.At this point, the liquid starts converting to vapor.

When the intermolecular force of attraction increases between the molecules, the boiling point of molecules also increases.

Intermolecular force

Intramolecular forces are well-known forces that work between the molecules as they hold atoms of the molecule together within a molecule.Intermolecular forces exist between molecules of any compound, such as water molecules.

Explanation

Acetic acid has a higher boiling point based on molecular weight and lower surface tension due to its higher polarity related to the water. It has high hydrogen bonding. It has a high boiling point because of a higher intermolecular force.

The inductive effect is present in chloroacetic acid –I because of the chlorine atom. The electron density is reduced over the already weakened O-H bond in the carboxylic moiety, making it a stronger acid. Due to the inductive effect and strong intermolecular interactions, it has a higher boiling point.

The acetate ester is a polar compound.

But it has no hydrogen atom, which will attach directly to an oxygen atom in the molecules. That's why acetate ester molecules cannot form intermolecular hydrogen bonding with another molecule and thus have considerably lower boiling points.