Why is phenol acidic enough to react with NaOH, but ordinary ethanol is not?
Both can lose the O–H proton, but the stability of what's left decides the acidity.
Both can lose the O–H proton, but the stability of what's left decides the acidity. When phenol loses H⁺, the resulting phenoxide ion spreads its negative charge into the benzene ring by resonance, making it stable — so phenol readily gives up the proton. Ethanol's alkoxide has no such stabilisation (alkyl groups even push electron density onto the O), so ethanol holds its proton and isn't acidic enough to react with NaOH.
Key point
Resonance stabilises the phenoxide ion, so phenol is far more acidic than an alcohol.
Common mistake
assuming all O–H groups are equally acidic.
Memory tip
charge spread by resonance = stronger acid (phenol > water > alcohol).
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