Acidity at phenol and Aliphatic alcohols are depend on the stability at conjugate base.
Here,
Phenoxide ion is more stable than Alkoxide ion. because - In phenoxide ion Negative charge (e- density) on oxygen atom delocalized with bezene ring and reduced charge density on oxygen atom (via Resonance),
Stabilized the phenoxide ion -
But in case at Alkoxide ion Negative charge localized on oxygen atom,that's why phenoxide ion is more stable than alkoxide ion.
∴ Phenol is more acidic than Aliphatic Alcohols.
