Re: NANFA-L-- hardness and pH

Jeff Grabarkiewicz (threehorn_wartyback-in-yahoo.com)
Fri, 26 Aug 2005 13:24:39 -0700 (PDT)

The difference between acidity and a low pH or vice versa with alkalinity and high pH is not always clear to people....For example, HCl and H2SO4 can have the same pH but very different acidities. From what I remember, it depends on how freely hydrogen dissociates (equilibrium constant Ka) and simply how much H there is (triprotic vs. diprotic vs. monoprotic acids) under ideal conditions. For alkalinity, it depends on the amount of carbonate, bicarbonate, hydroxides, and other compounds are floating around in solution.

>From my lab days, I remember expressing acidity in ppm of calcium carbonate to bring the solution to a pH of 7.2 I remember spending lots of time trying to titrate sulfuric and phosphoric acid!

I don't know if this helps-in-all, but gives some background anywho.

Laura Burbage <leuhrich-in-yahoo.com> wrote:
I've got a chemistry question. The water here in
Athens is very soft, less than 2 GH and KH. But it is
persistently alkaline, around pH 8 or more. Why on
earth is this? What can I do when I am working with
tap water to raise the hardness without raising the
pH? How can I lower the pH?

Laura
North Oconee River
Georgia
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