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Chemistry
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At 25oC, the Ka for hypochlorous acid HOCl is 3.5E-8. Calculate the concentration of the H3O+ in an aqueous solution of 0.8 M HOCl.

Feb 9th, 2015

First need an equation:

HOCl(aq) + H2O(l) ------> OCL-(aq) + H3O+(aq)

Next, Ka = [H+][OCl-] / HOCl

Next: HOCl(aq) <-----------> H+(aq) + OCl-(aq)
Initial. 0.2 0 0
Change -x +x +x
Equib: 0.2-x +x +x

Next:3.5 x 10(exp-8) = x(exp2) / 0.2 -x

since the Ka is so small an approximation may be used

(0.2 - x) is approximately 0.2

3.5 x 10 (exp-8) = x(exp2) / 0.2

Feb 9th, 2015

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