You perform your first titration using your NaOH with a KHP solution. Your KHP solution is made with 0.4783 g of KHP.

The initial amount of NaOH in your pipette is 15.74 mL and the final amount in your buret is 35.10 mL when the indicator changes colour. Determine the concentration of your NaOH solution. Write your answer to four decimal places without units.