Alcohols, Phenols, and Ethers — Chemistry STD 12 Science — Question

2. n-butyl alcohol > n-butaraldehyde > n-pentane > diethylether.

Explanation:
As we know that the higher the extent of intermolecular Hydrogen bonding in a molecule, the higher its boiling point becomes.
By that logic, n-butyl alcohol will have a higher boiling point than n-butyraldehyde due to the presence of more extensive H-bonding.
Again, there is no H-bonding present in both diethyl ether and n-pentane. But as n-pentane has a higher molecular weight than that of diethyl ether, it will possess a higher boiling point.