Oxidation of Ethanol and Carboxylic Acids
Ethanol can be oxidised in three main ways, each producing different results. Complete combustion happens when ethanol burns in air, producing carbon dioxide and water with a faint blue flame - this is what occurs in alcohol burners.
Microbial oxidation is far more interesting for everyday life. When wine or beer is left open for several days, bacteria use oxygen to convert the ethanol into ethanoic acid, giving that sharp vinegary taste. This same process is how vinegar is actually made commercially.
The third method involves heating ethanol with potassium dichromate in dilute sulfuric acid. This redox reaction also produces ethanoic acid and is the chemical basis for breathalyser tests - the colour change from orange dichromate to green chromium ions shows how much alcohol is present.
Carboxylic acids all contain the COOH functional group. The most common ones you'll encounter are methanoic acid (HCOOH) and ethanoic acid (CH₃COOH). These are weak acids because the hydrogen in the COOH group doesn't come off as easily as in strong acids like sulfuric acid. They still react with metals and carbonates though, just less vigorously, forming carboxylate salts (like ethanoate from ethanoic acid).
Quick Tip: Remember that carboxylic acids are weak acids - they react like other acids but much more gently!
