Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: ljdsmith on April 05, 2005, 05:53:54 PM
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I'm not sure as to what the purpose is for bubbling a solution with an inert gas.
For example a solution of a given species that is in equilibrium with its gas phase--would bubbling with an inert gas cause a shift in the equilibrium to exsolve the gas phase (of the species not the inert gas) because N2 is being dissolved?
Also, does N2 disolve to form NH4+ during bubbling and cause the pH to rise?
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Its to drive oxygen out of the solution.
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Only oxygen?
If it was a carbonate system would CO2 exsolve?
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Well, the most common problem with reactions is oxygen, and it's the most abundant gas next to nitrogen in the air, so oxygen is most common. However, bubbling (also called sparging) with an inert gas like nitrogen or argon serves to displace all dissolved gasses in a solvent with nitrogen or argon, which, for the most part, are hamless to reactions. You can also look up a method called 'freeze-pump-thaw', which does the same thing. But to answer your question directly, yes, carbon dioxide is also displaced.
And no, under normal conditions (like you'd have to make some REALLY strange conditions) nitrogen won't form ammonium ion. However, you may see pH changes as the more liquid that you evaporate from solution, the more concentrated it gets, and thus the pH may change depending on the solution.
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Also, does N2 disolve to form NH4+ during bubbling and cause the pH to rise?
That would be a dream for nitric acid producers ;)