How does the presence of the -OH group in phenol influence its reactivity in electrophilic aromatic substitution reactions, and why does it direct incoming groups to ortho and para positions?

The presence of the -OH group in phenol enhances its reactivity in electrophilic aromatic substitution (EAS) reactions compared to benzene. The oxygen donates electron density to the ring through resonance, activating the aromatic system. This makes the ring more nucleophilic and reactive toward electrophiles. The -OH group also directs incoming groups to ortho and para positions due to resonance stabilization of the intermediate sigma complex. The lone pairs on oxygen can delocalize into the ring, stabilizing the positive charge at ortho and para positions. This resonance assistance favors the formation of products at these positions in EAS reactions on phenol.