100 mL of 1.0 M formic acid (HCOOH) is titrated with 1.0 M sodium hydroxide (NaOh).

Question

The Approximate pKa is 4

At the pKa, what fraction of the carboxyl group will have been converted to COO-?

Answer 1

Do you mean at a pH = pKa, what is the fraction?
pH = pKa + log(base)/(acid)
4 = 4 + log (base)/(acid)
(base)/(acid) = 1
So 50% has been converted.