You are asked to prepare 2 L of 50 mM sodium phosphate pH 7.0. The

Question

pK2 of phosphate is 6.8. What are the amounts of sodium phosphate mono
basic monohydrate (NaH2PO4 • 1H2O, MW=137.99 Da) and anhydrous sodium
phosphate dibasic (Na2HPO4, MW=141.96 Da) that must be weighed out?

Answer 1

See your other question about tris and tris-HCl.
In this problem determine the (Base) and (Acid), then convert to mols you will need, then grams = mols x molar mass = ?
Post your work if you get stuck.