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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: ayyaddict on April 08, 2012, 10:57:25 PM

Title: Why does the ionization of ammonia occur in aqueous solution?
Post by: ayyaddict on April 08, 2012, 10:57:25 PM

Ionization of Ammonia: NH₃ (aq) + H₂O (l) --> NH₄⁺(aq) + OH^-(aq)

I have calcuated the Delta G_rxn to be positive (+27.02 kj/mol) and the question asks why the ionization of ammonia actually occurs in aqueous solution despite the reaction being non-spontaneous? Is there a way for this reaction to actually occur?

Title: Re: Why does the ionization of ammonia occur in aqueous solution?
Post by: Dan on April 09, 2012, 05:37:19 AM

It's a dynamic equilibrium (http://en.wikipedia.org/wiki/Dynamic_equilibrium), a positive :delta: G just means the equilibrium lies on the left side.

NH₃ (aq) + H₂O (l) ::equil:: NH₄⁺ (aq) + OH^-(aq)

Title: Re: Why does the ionization of ammonia occur in aqueous solution?
Post by: ayyaddict on April 09, 2012, 12:22:38 PM

Ah, that makes sense. Thanks very much Dan.