Because an acid–base indicator is a weak acid, it can be titrated with a strong base. Suppose you titrate 25.00 mL of a 0.0100 M solution of the indicator p-nitrophenol, HOC₆H₄NO₂, with 0.0200 M NaOH. The pK_a of p-nitrophenol is 7.15, and it changes from colorless to yellow in the pH range from 5.6 to 7.6.

(a) Sketch the titration curve for this titration.

(b) Show the pH range over which p-nitrophenol changes color.

(c) Explain why p-nitrophenol cannot serve as its own indicator in this titration.