Alcohols as acids and bases

Many applications of the alcohols depend on their ability to act both as acids and as bases. (See the review of these concepts in Section 2-3.) Thus, deprotonation gives alkoxide ions. We shall see how structure affects pK values. The lone electron pairs on oxygen render alcohols basic as well, and protonation results in alkyloxonium ions. 

The acidity of alcohols in water is expressed by the equilibrium constant K. 

Alcohol (ethanol) consumption, particularly when excessive, may lead to the burning sensation in the chest that is called heartburn. This condition is not due to the acidity of ethanol, but rather to increased production of stomach acid. It is exacerbated by the relaxation of the lower esophageal sphincter, a valve that normally prevents stomach contents from moving up into the esophagus ( acid reflux ). 

Making use of the constant concentration of water (55 mol L Section 2-3), we derive a new equilibrium constant K.  

Why are alcohols acidic, whereas alkanes and haloalkanes are not The answer lies in the relatively strong electronegativity of the oxygen to which the proton is attached, which stabilizes the negative charge of the alkoxide ion. 

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