Acid-base equilibria

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I was just wondering why boric acid doesn’t react with sodium carbonate to release carbon dioxide. I know it’s a weak acid, but why does that affect this reaction?

Igloo replies ...
 
Boric acid is a weaker acid than carbonic acid, H₂CO₃, which is the acid formed when carbonate ions gain protons. It is an unstable acid which decomposes easily into carbon dioxide and water.
 
The reaction of carbonates with acids can be summarized by the following ionic equation:
CO₃^2– + 2H⁺ <=> CO₂ + H ₂ O
 
Since boric acid is a very weak acid it barely ionises in aqueous solution and it is not a strong enough proton donor to give hydrogen ions to carbonate ions.
 
An acid has to be a stronger acid than carbonic acid to shift the equilibrium to the right and produce carbon dioxide.

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updated: 09 December 2003