why is phenol stronger acid than cyclohexanol?

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Phenol is more acidic than cyclohaxanol. Pka value of alcohols is 16-17 while of phenol is 10. Phenol gives a stable conjugate base (phenoxide) after ionization. This stability of phenoxide is due to resonating structures of phenoxide. 

Resonating structures of phenoxide.

Electrons are delocalized on whole benzene ring make phenoxide a stable conjugate base. 

On the other hand alkoxide - conjugate base of non aromatic alcohols- don't have delocalized electrons rather electrons of alkoxide are localized on oxygen atom. These localized electrons rapidly rebond the ionized proton H+. 


That's why phenol is more acidic as compare to cyclohaxanol a cyclic alcohol .


Remember more pka value means weak acid and vice versa.

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