posted by jean .
write an equation for which component of the phosphate buffer (H2PO4-/ HPO4^2-) reacts when HCl is added. Do the same for NaOH.
I think that the H2PO4- will react with the NaOH but its only a guess and I'm confused as to how I would go about doing this.
You guessed wrong.
You have H2PO4^- and HPO4^2-
Which is the acid and which is the base? H2PO4^- is the acid. Why? Because it is the one with extra H^+. The HPO4^2- is the base because it is the one with fewer H (and the one accepting protons).
H2PO4^- ==> H^+ + HPO4^2-
This shows the H2PO4^- donating a proton and HPO4^2- accepting a proton.