The indicator used had a p Kind = 3.50. HNO2 is a weak acid with a Ka = 1.9 X 10^-4. A 20.00mL aliquot of a 1.000M solution of HNO2 was titrated with 1.000M NaOH. Determine the numbers of mL of NaOH are essential to reach the end point of the titration?