Question

Why do alcohols possess higher boiling points as compared to those of corresponding alkanes?

Answer 1

The alcohols are made up of hydrogen bonds and as we know that hydrogen bond is the strongest bond among all the bonds. So due to this alcohol's force of attraction between the particles is very strong and rigid. But van der waals force of attraction in alkanes is weak as compared to hydrogen bonds. The hydroxyl group in alcohol is responsible for hydrogen bonding.

Complete step by step answer:
A hydrogen bond (frequently informally abbreviated H-bond) is a frequently electrostatic pressure of enchantment between a hydrogen (H) atom that is covalently bound to a extra electronegative atom or group, in particular the second-row elements such as nitrogen (N), oxygen (O), or fluorine (F) — are considered to be the hydrogen bond donor (Dn) — and any other electronegative atom bearing a lone pair of electrons — are considered to be the hydrogen bond acceptor (Ac).
Alcohols own better boiling points as compared to the ones of corresponding alkanes due to intermolecular hydrogen bonding. Hydrogen bonds are formed between the hydroxyl organizations of the two molecules of an alcohol. Due to this, several molecules are associated to shape a huge molecule.

Additional Information:
The elements affecting the boiling/melting points of alcohols aren't handiest hydrogen bonds, however additionally van der Waals dispersion forces and dipole-dipole interactions.
The hydrogen bonds and dipole-dipole interactions will continue to be pretty equal throughout the series of alcohols. The van der Waals dispersion forces increase as the length of the hydrocarbon chain will increase. This is because of the growth in the number of electrons within the molecules, which in turns increases the energy and size of the briefly brought about dipole-dipole attraction. Hence, extra energy is required to overcome the intermolecular forces, ensuring the increase in boiling/melting points.

Note: As we know the hydrogen bonding is p[resent in alcohols due to hydroxyl group so the intermolecular force of attraction will be strong and this makes the compound breaking ability low, so the melting point and boiling point of alcohols will be high. While in alkanes there is van der waals force of attraction so the breaking ability of alkanes will be more as compared to alcohols, so the melting and boiling point of alkane will be less than alcohol.