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Roq
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I'm trying to conceptually understand a question that I was wondering about while reading about Acid and Base Equilibria.
Since a strong acid such as HCl completely reacts to give Cl- and the hydronium ion, and Cl- is then inert, then the only equilibrium going on is Kw. Kw = KbKa = [OH-][H+] = 1x10^-14...
I always thought that when OH- or H+ were produced, the Kw would balance itself like other reactions, and in this case it would mean the reaction going to the reactant direction.
Since the equilibrium would be restored by reacting [OH-] and [H+], they would both decrease on a one to one basis, and it could not just decrease the [OH-] without in turn decreasing [H+] at the same time.
That seems logical to me, but given the way these equations are calculated (at least in my class), like in the case of HCl, you would have an equal [HCl] and [H+] concentration, and there is no subtraction to account for the equilibrium of Kw. While this may not matter if you are dealing with 1 M of HCl, if your concentration is very small, like around 1x10^-7, then a large percentage of it would be subtracted as Kw is restored.
Perhaps it is irrelevant because there is little use for acids and bases at such tiny concentrations, but is this correct?
Since a strong acid such as HCl completely reacts to give Cl- and the hydronium ion, and Cl- is then inert, then the only equilibrium going on is Kw. Kw = KbKa = [OH-][H+] = 1x10^-14...
I always thought that when OH- or H+ were produced, the Kw would balance itself like other reactions, and in this case it would mean the reaction going to the reactant direction.
Since the equilibrium would be restored by reacting [OH-] and [H+], they would both decrease on a one to one basis, and it could not just decrease the [OH-] without in turn decreasing [H+] at the same time.
That seems logical to me, but given the way these equations are calculated (at least in my class), like in the case of HCl, you would have an equal [HCl] and [H+] concentration, and there is no subtraction to account for the equilibrium of Kw. While this may not matter if you are dealing with 1 M of HCl, if your concentration is very small, like around 1x10^-7, then a large percentage of it would be subtracted as Kw is restored.
Perhaps it is irrelevant because there is little use for acids and bases at such tiny concentrations, but is this correct?