Phenol

First, react phenylamine with HNO₂ or NaNO₂ and dilute acid below 10 °C to form a diazonium salt. Then, warm the diazonium salt with H₂O to produce phenol.

Phenol reacts with NaOH(aq) to produce sodium phenoxide. This demonstrates phenol's acidic character as it donates a proton to the base.

Phenol reacts with sodium metal (Na(s)) to form sodium phenoxide and hydrogen gas (H₂).

Phenol reacts with diazonium salts in NaOH(aq) to give azo compounds. These reactions are important in the synthesis of dyes.

Phenol reacts with dilute HNO₃(aq) at room temperature to undergo nitration. This produces a mixture of 2-nitrophenol and 4-nitrophenol.

Phenol reacts rapidly with Br₂(aq) to form 2,4,6-tribromophenol. No halogen carrier is required, unlike the bromination of benzene.

Phenol's conjugate base, the phenoxide ion, is stabilized by delocalization of the negative charge into the benzene ring. This stabilization makes phenol more willing to donate a proton, increasing its acidity compared to water and ethanol, where the negative charge on the conjugate base cannot be delocalized to the same extent.

The lone pair of electrons on the oxygen of the phenol's -OH group is partially delocalized into the benzene ring. This increases the electron density of the ring, making it more susceptible to electrophilic attack, and thus requiring milder reaction conditions compared to benzene.

The hydroxyl group (-OH) in phenol is an activating and 2,4-directing group. This means that electrophilic substitution reactions, like nitration and bromination, will preferentially occur at the 2-, 4-, and 6-positions of the benzene ring.

Similar to phenol, 1-naphthol will react rapidly with aqueous bromine. Expect to see substitution at the positions ortho and para to the hydroxyl group on the naphthalene ring, likely resulting in a polybrominated product analogous to 2,4,6-tribromophenol.