The acidic nature of phenol can be proven with the two reactions shown below :
(i) Reaction with sodium: Phenol reacts with active metals like sodium to liberate Hydrogen gas.
(ii) Reaction with NaOH: Phenol dissolves in NaOH to form sodium phenoxide and water.
Phenol’s acidity is higher than that of ethanol. This is because the phenoxide ion undergoes resonance and stabilizes after losing a proton, whereas the ethoxide ion does not.