Correct order of boiling points in the following is:

A. \(CH_3CHO\)

B. \(CH_3COOH\)

C. \(CH_3CH_2OH\)

D. \(CH_3CH_3\)

E. \(CH_3CH_2Cl\)

Choose the correct answers from the options given below:

B, C, A, E, D

The correct answer is option 4. B, C, A, E, D.

Let us break down the factors that determine the boiling points of the given compounds, focusing on the types of intermolecular forces at play:

A. \(CH_3CHO\) (acetaldehyde):

Intermolecular forces: Acetaldehyde has dipole-dipole interactions because of the polar carbonyl group (-C=O), but it lacks the ability to form hydrogen bonds. Dipole-dipole interactions are weaker than hydrogen bonds, so acetaldehyde has a lower boiling point than both acetic acid and ethanol.

Boiling point: Moderate, due to dipole-dipole interactions but no hydrogen bonding.

B. \(CH_3COOH\) (acetic acid):

Intermolecular forces: Strong hydrogen bonding due to the carboxylic acid group. Hydrogen bonding occurs between the hydrogen atom of the hydroxyl group (-OH) and the oxygen atom of the carbonyl group (-C=O) in other acetic acid molecules. This creates dimers, which significantly increase the boiling point.

Boiling point: Highest in the group due to strong hydrogen bonds.

C. \(CH_3CH_2OH\) (ethanol):

Intermolecular forces: Ethanol also exhibits hydrogen bonding, but it is less extensive compared to acetic acid. The alcohol group (-OH) in ethanol allows hydrogen bonding, though the lack of a second oxygen atom (like in acetic acid) makes the hydrogen bonding less effective.

Boiling point: Lower than acetic acid but still relatively high due to hydrogen bonding.

D. \(CH_3CH_3\) (ethane):

Intermolecular forces: Ethane only experiences weak London dispersion forces (van der Waals forces) as it is a nonpolar molecule with no significant dipole. These forces are the weakest type of intermolecular interaction.

Boiling point: Lowest among the compounds because London dispersion forces are the weakest.

E. \(CH_3CH_2Cl\) (ethyl chloride):

Intermolecular forces: Ethyl chloride has dipole-dipole interactions due to the electronegative chlorine atom, but these are weaker than the forces in acetaldehyde. It lacks hydrogen bonding, so its boiling point is lower than acetaldehyde.

Boiling point: Lower than acetaldehyde because dipole-dipole interactions are not as strong as in acetaldehyde.

Summary of boiling points:

B.\(CH_3COOH\) has the highest boiling point due to strong hydrogen bonding.

C.\(CH_3CH_2OH\) comes next, with somewhat weaker hydrogen bonding.

A.\(CH_3CHO\) has moderate dipole-dipole interactions but no hydrogen bonding.

E. \(CH_3CH_2Cl\) has weaker dipole-dipole interactions than acetaldehyde.

D. \(CH_3CH_3\) has the lowest boiling point due to only weak London dispersion forces.

Thus, the correct order of boiling points is: B (acetic acid) > C (ethanol) > A (acetaldehyde) > E (ethyl chloride) > D (ethane).

This corresponds to option 4: B, C, A, E, D.