A mass of 2.84 g Na2HPO4 is measured out and after the addition of 10.0 mL of water, 15.0 mL of a 1.0 M HCL solution is immediately added. What is…

A mass of 2.84 g Na2HPO4 is measured out and after the addition of 10.0 mL of water, 15.0 mL of a 1.0 M HCL solution is immediately added. What is the final pH if 10.0 mL of 1.0 M NaOH solution is now added to this buffer? Show the titration reaction.