Problem- Enough of a monoprotic acid is dissolved in water to produce a 0.0190M solution. The pH of the resulting solution is 6.17. Calculate the Ka for the acid.
I've tried the following answers
2.35x10^-11
2.40x10^-11
2.41x10^-11
And was told I'm incorrect. So I'm supposing that maybe there was rounding error or a tiny step that I not recalled when trying to work the problem.
Solve the above problem and provide steps with explanation