[ebsnyder]

Any help on this would be appreciated.
 You have 0.5M solution of dichloroacetic acid. Assuming a case 1 scenario, where H3O+ from water was neglected, calculate the relative uncertainty as a percentage, in pH using the simplified method as compared with the exact solution.
At what concentration of dichloroacetic acid would this uncertainty be less than or equal to 1%?

[enahs]

That is a nice question.
Care to at least attempt it first?

http://www.chemicalforums.com/index.php?topic=57.0