Identify the correct order of boiling points of the following compounds: \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OH} \quad\) (1) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CHO}\) (2) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{COOH}\) (3) (a) \(1>2>3\) (b) \(3>1>2\) (c) \(1>3>2\) (d) \(3>2>1\)

Understanding intermolecular forces is essential when comparing the boiling points of organic compounds. Intermolecular forces are the attractions between molecules, which affect the physical properties of a substance, including melting and boiling points.

There are several types of intermolecular forces, but the most relevant in the context of organic compounds are hydrogen bonding, dipole-dipole interactions, and London dispersion forces. Hydrogen bonds are particularly strong types of dipole-dipole interactions that occur when a hydrogen atom is bonded to an electronegative atom like oxygen or nitrogen and is in proximity to another electronegative atom. Alcohols, for instance, can form hydrogen bonds due to their -OH groups, leading to higher boiling points.

Dipole-dipole interactions occur between polar molecules, such as aldehydes, where the difference in electronegativity between atoms leads to a partial positive and negative charges, resulting in attractions between oppositely charged ends of different molecules. These are weaker than hydrogen bonds but still significantly affect boiling points.

Lastly, London dispersion forces are the weakest intermolecular forces and are present in all molecules, especially nonpolar molecules. They arise due to the temporary fluctuations in electron density, which create instantaneous dipoles that induce corresponding dipoles in neighboring molecules, leading to an attraction. Although weak, these forces are significant in large molecules with more surface area.

Functional groups are specific groups of atoms within molecules that have characteristic properties and react in predictable ways. They are responsible for the distinctive chemical reactions of those molecules. In organic chemistry, functional groups define the structure of families of compounds and influence their chemical behavior.

Common functional groups include alcohols (-OH), aldehydes (-CHO), and carboxylic acids (-COOH). Alcohols are organic compounds that contain one or more hydroxyl groups attached to a carbon atom. The presence of -OH allows for hydrogen bonding, which increases the boiling point.

Aldehydes have a carbon atom double-bonded to an oxygen atom and single-bonded to a hydrogen atom (carbonyl group at the end of the carbon chain), and they generally exhibit moderate boiling points due to dipole-dipole interactions. Carboxylic acids contain both a carbonyl and a hydroxyl group (COOH) bonded to the same carbon, which enables them to form strong intermolecular hydrogen bonds, usually resulting in even higher boiling points than alcohols and aldehydes due to their ability to create dimeric structures in a liquid state.

Hydrogen bonding has a profound effect on the boiling point of organic compounds. It's a special type of dipole-dipole attraction between a hydrogen atom, which is covalently bonded to a highly electronegative atom such as oxygen or nitrogen, and another electronegative atom with a lone pair of electrons.

When hydrogen bonds form, they significantly increase the amount of energy required to separate molecules from each other during the phase change from a liquid to a gas, hence increasing the boiling point of the substance. For example, the presence of an -OH group in alcohol allows it to engage in hydrogen bonding, elevating its boiling point. In carboxylic acids, two hydrogen bonds can form per molecule, leading to the formation of dimers and an even greater boiling point elevation, as seen in compound 3 from the exercise.

When comparing alcohols and carboxylic acids to compounds with similar molar masses but without hydrogen bonding ability, like aldehydes, the influence of hydrogen bonding is particularly evident. Thus, understanding the nature and strength of hydrogen bonding is crucial when evaluating why some organic compounds boil at higher temperatures than others.