Question

Select the correct order of boiling point:

• A. diethyl ether $>$ n-butyl alcohol $>$ n-butaraldehyde $>$ n-pentane
• B. n-butyl alcohol $>$ n-butaraldehyde $>$ n-pentane $>$ diethylether
• C. n-pentane $>$ n-butaraldehyde $>$ n-butyl alcohol $>$ diethylether
• D. n-butyl alcohol $>$ n-butaraldehyde $>$ diethylether $>$ n-pentane

Answer 1

The correct option is B n-butyl alcohol $>$ n-butaraldehyde $>$ n-pentane $>$ diethylether

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.

Therefore, the correct order is-
n-butyl alcohol $>$ n-butyraldehyde $>$ n-pentane $>$diethyl ether.

Hence, the correct option is B.