Electron-withdrawing groups enhance the acidic strength of phenol, with a more pronounced effect at ortho and para positions. Effective delocalization of negative charge in the phenoxide ion occurs when the substituent is at these positions.

Charge delocalization, illustrated by resonance structures I-V, increases the stability of phenoxide ions. The phenol molecule is less stable due to charge separation in its resonance structures, favoring the ionization of phenol.

In alkoxide ions, the negative charge is localized on oxygen, while in phenoxide ions, the charge is delocalized. The delocalization of charge in phenoxide ions contributes to their increased stability compared to the localized charge in alkoxide ions.

The higher electronegativity of sp² hybridized carbon in phenol decreases electron density on oxygen, increasing the polarity of the O-H bond. This leads to greater ionization of phenols compared to alcohols.

The hydroxyl group in phenol is directly attached to the sp² hybridized carbon of the benzene ring, acting as an electron-withdrawing group. This, along with resonance structures, results in a positive charge on the oxygen, making phenols stronger acids than ...