Calculate the pH of a buffer solution obtained by dissolving 15.0 g of KH2PO4 (MM = 136.1 g/mol) and 32.0 g of Na2HPO4 (142.0 g/mol) in water and then diluting to 1.00 L.

Question

anitaasks · Answer

You need the Ka of KH2PO4, which is 6.2*10^-8. Then you use pH=pKa + log ([base]/[acid]). You can find the concentrations by dividing your given masses by the molar masses you have indicated. Then, you just plug in all your numbers.