Explain the acidic nature of phenols.

Explanation

Phenols react with active metal like sodium to forin sodium phenoxide.
`2C_(6)H_(5)OH_2Na to 2C_(6)H_(5)ONa_H`
Phenols react with aqueous sodium hydroxide to form sodium phenoxide.
`C_(6)H_(5)OH+NaOH to C_(6)H_(5)ONa+H_(2)O`
The above reactions shows that phenols are acidic in nature, Le. phenols are Bronsted acids.
The acidic nature of phenol is due to :
• The hydroxyl group ir phenol is directly attached to `sp^(2)` hylbridised carbon of benzene ring which acts as an electron withdrawing group. Due to this phenol easily donates hydrogan ion.
• The phenoxide ion is more stable due to resonance stabilisation and hence it favours the ionisation of phenols.
• The electron withdrawing group increases the acidity of phenols.
Ex: Nitrophenols are more acidic than phenols.
• The electron donating group decreases the acidity of phenols.
Ex, Cresols are less acidic than phenols.