Question

A 5.00 mL sample of H3PO4 solution of unknown concentration is titrated with a 0.1090 M NaOH solution. A volume of 7.12 mL of the NaOH solution is required to reach the equivalence point. What is the concentration of the unknown H3PO4 solution?

Answer 1

the answer is that first you add 5.00+7.12=12.12