Question

Ethanol and dimethyl ether form a pair of of functional isomers. The boiling point of ethanol is higher than that of dimethyl ether due to the presence of
A. hydrogen bonding in ethanol
B. hydrogen bonding in dimethyl ether
C. `-CH_(3)` group in ethanol
D. `-CH_(3)` group in dimethyl ether

Answer 1

Correct Answer - A
The `OH` group in alcohols contains a `H`bonded to a highly electronegative oxygen atom. Therefore, it is capable of forming intermoecular `H-`bond as shown below:
`R-underset(H)underset(|)overset(delta-)(O)….overset(delta+)(H)-underset(delta-)overset(R)overset(|)(O)....overset(delta+)(H)-underset(R )underset(|)overset(delta-)(O)....overset(delta+)(H)-overset(R )overset(|)(O)`
It is due to the presence of intermolecular hydrogen bonding that alcohols have higher boiling points corresponding to ether which are incapable of exhibiting intermolecular `H` bonding.