Which one of the following compounds shows the presence of intramolecular hydrogen bond?
- H2O2
- HCN
- Cellulose
- Concentrated acetic acid
Answer
(3) Cellulose
Solution
∵ Intramolecular hydrogen bond is formed when the H atom lies between two electronegative atoms of the same molecule.
H2O2 ⇒ H-bonds between different H2O2 molecules (intermolecular).
HCN ⇒ H-C N H-C N chains (intermolecular).
Concentrated acetic acid ⇒ exists as a dimer held by two intermolecular H-bonds.
Cellulose ⇒ one long chain of β-D-glucose units; the –OH group of one glucose unit forms an H-bond with the O atom of the next unit of the same chain (intramolecular), besides H-bonds between neighbouring chains.
∴ Cellulose shows intramolecular hydrogen bonding.
Answer: (3)