Electron Distribution in an Alcohol

• Oxygen atom of Hydroxyl group
  • Weakly Basic (Due to lone-pairs.)
  • Nucleophilic
• Hydrogen atom of Hydroxyl group
  • Weakly Acidic
• Upon protonation it converts into a good leaving group ($-H_{2}O$) from a poor one ($-OH$). Protonation also causes the carbon to be even more positive due to the higher electron withdrawing nature of ($H_2{O}^{+}-$). This makes it even more susceptible to nucleophilic attacks.
• At a high enough temperature and in absence of a good nucleophile, protonated alcohols are capable of undergoing $E1$ and $E2$ reactions. (Alcohol dehydrations.)