Which type of bond is present between the oxygen of the –OH group and carbon in an alcohol?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Sigma (σ) bond
In an alcohol, carbon and oxygen are joined by a single bond, formed by the head-on overlap of an sp3 orbital of carbon with an sp3 orbital of oxygen. A head-on overlap gives a sigma (σ) bond.
Why the other options are incorrect
Option (1) Pi (π) bond — Incorrect. A π bond comes from sideways overlap of p orbitals and is found only in a double or triple bond; the C–O bond of an alcohol is single.
Option (3) Both σ and π bonds — Incorrect. One σ and one π bond together make a double bond, as in the C=O group of aldehydes and ketones, not the C–OH of an alcohol.
Option (4) Hydrogen bond — Incorrect. Hydrogen bonding is a weak intermolecular attraction between the –OH of one alcohol molecule and the oxygen of another; it does not join oxygen to carbon within the molecule.
NCERT (2026-27 edition):
7.3 Structures of Functional Groups – “In alcohols, the oxygen of the –OH group is attached to carbon by a sigma (σ) bond formed by the overlap of a sp3 hybridised orbital of carbon with a sp3 hybridised orbital of oxygen.”