A student performed a titration to determine the molarity of a solution of
HCl(aq). The student pipetted 5.0 mL of the acid into a flask, added 5 drops of
phenolphthalein indicator to the flask, then titrated the acid with 0.50 M NaOH in
a buret. The following results were obtained at different volumes: 6,0 mL was
clear: 7.0 mL was clear; 8.0 ml was light pink but faded back to clear: 9.0 mL was
pink. What was the volume in the buret when the acid was neutralized?

6.0 mL
O 7.0 mL
O 8.0 mL
9.0 mL