You are asked to make 250 mL of 150 mM phosphate buffer, pH 6.4, from sodium dihydrogen phosphate, NaH2PO4 (MW =120 g/mol). For the following responses, show calculations when applicable.

(a) How much of the NaH2PO4 should the you weigh out?

(b) In what volume of water should the NaH2PO4 be dissolved? Explain.

(c) Should the biochemist expect to use NaOH or HCl to adjust the pH to 6.4? Explain.

(d) Calculate the expected volume of the reagent chosen in part (c) needed to adjust the pH of the phosphate solution to pH 6.4. Assume 6M of reagent to be used.

(e) In one-two sentences, briefly describe how the strong acid or base reagent should be added to the phosphate when adjusting the pH to 6.4.

(f) Once the pH is adjusted is there anything left to do? Explain.