Structure of Functionl Group Preparation and Properties
→ In alcohols oxygen of – OH group is bonded by σ (sigma) bond with carbon atom. This sigma (σ) bond is formed by overlapping of sp3 hybrid orbital of carbon atom and sp3 hybrid orbital of oxygen atom.
→ In alcohols 
bond angle is less then tetrahedral angle (109°28’).
→ This decrease occurs due to repulsion between unshared electron pair of oxygen atom.