posted by John on .
A 50.0 mL sample of 0.51 M benzoic acid, C6H5COOH, a weak monoprotic acid, is titrated with 0.40 M NaOH. Calculate the pH at the equivalence point. Ka of C6H5COOH = 6.5 10-5.
what am i supposed to do with this?
The pH at the equivalence point is determined by the hydrolysis of the salt, in this case, sodium benzoate.
C6H5COO^- + HOH ==>C6H5COOH + OH^-
Now, write the Keq expression, set up an ICE chart, and solve for OH^-. Then change to pOH, then to pH. Post your work if you get stuck. Kb for the base (the C6H5COO^-) is Kw/Ka.