A 0.0200 M solution of NaOH is being used to titrate 20.00 mL of 0.0400 M HCl using bromthymol blue as indicator.

A 0.0200 M solution of NaOH is being used to titrate 20.00 mL of 0.0400 M HCl using bromthymol blue as indicator. The end point, corresponding to a pH of 7.0, occurs when 40.00 mL of base has been added. Calculate the volumes of titrant that correspond to the beginning and to the end of bromthymol blue’s transition range, 6.0–7.6.