Question

Which of the following molecules are expected to exhibit inter-molecular $H-$bonding?

• A. Acetic acid
• B. o-Nitrophenol
• C. m-Nitrophenol
• D. o-Boric acid

Answer 1

The correct option is A Acetic acid

The two conditions given for hydrogen bonding are:

1) A hydrogen atom must be covalently bonded to $O,N$ or $F$ atom. We can understand this part, as $O,N$ and $F$ are highly electronegative and will leave the $H$ with a positive dipole (more or less a $H^{+}$ ion).

2) The other condition is that the atom with a lone pair which the $H$ is hydrogen-bonded to must be $O,N$ or $F$.

Acetic acid dimerises as shown in the image and there exists an inter-molecule are $H-$bonding between the molecules.