Using an aqueous solution of 75.00 mL of HCOOH is titrated with a 0.150 M sodium hydroxide(aqueous solution ).after observations it is found the NaOH solution of that 21.25 mL is required to reach the equivalence point.. compute the pH if NaOH solution of the 10.00 mL has been mixed. pKa of HCOOH = 3.74