The reaction shows the conversion of p-chloronitrobenzene to p-nitrophenol.

1. Type of Reaction: This is a Nucleophilic Substitution reaction where the chloride ion ($Cl^-$) is replaced by a nucleophile, the hydroxide ion ($OH^-$).
2. Reactivity: Aryl halides are generally less reactive towards nucleophilic substitution. However, the presence of an electron-withdrawing group (EWG) like $-NO_2$ at the ortho or para position withdraws electron density from the benzene ring, stabilizing the intermediate carbanion and facilitating the attack of the nucleophile ($OH^-$).
3. Conditions: While chlorobenzene requires drastic conditions (623 K, 300 atm) to react with NaOH, the presence of the nitro group at the para position lowers the required temperature to 443 K.