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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: sungirl322 on September 12, 2004, 09:19:36 PM

Title: need help with acid-base and Keq
Post by: sungirl322 on September 12, 2004, 09:19:36 PM

 ???, I am not sure how to determine the Keq of an acid base reaction. I thought it was the ka of the products/ the ka of the reactants. Please help

Title: Re:need help with acid-base and Keq
Post by: Donaldson Tan on September 13, 2004, 02:01:11 AM

HX + H₂O <-> H₃O⁺ + X^-

K_a = [ H₃O⁺ ] [ X^- ] / [ HA ]

The K_a term excludes the [H₂O] in the denominator as [H₂O] is fairly a constant in an aqueous system.

Just include [H₂O] in the denominator to convert K_a to K_eq

K_eq = [ H₃O⁺ ] [ X^- ] / [ HA ] [H₂O]