This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
Protonation refers to addition of H+ to oxygen of OH group. It is easier when O has more electron density, i.e. when nucleophilic character of O is more.
In alcohols the electron density on oxygen is high due to localization of its lone pair and electron donating nature of alkyl group. So their protonation is easy.
However in phenols, the lone pair of oxygen is in resonance with the benzene ring and thus is delocalized. So protonation of phenols is difficult.