Carboxylic Acid Deprotonation
Deprotonation of Carboxylic Acid
Carboxylic acids are fairly acidic. A carboxylic acid can be deprotonated to form a carboxylate. This is because the conjugate base is quite stable. The negatively charged oxygen atom can be further stabilized through resonance.
Since the carboxylates are so stable, carboxylic acids have a pKa around 5. Regular alcohols have a pKa of around 17. This makes carboxylic acids 1,000,000,000,000 (1 trillion or 10^12) times more acidic than alcohols.
Therefore, carboxylic acids react with bases to make carboxylate salts. For example, when carboxylic acids react with sodium hydroxide, or a very weak base like sodium bicarbonate (NaHCO3) for that matter, they make the sodium salt of a carboxylic acid. These acid salts are water-soluble. Then, if the solution is acidified, the carboxylic acid can be reformed.
