Phosphate buffer is a commonly utilized buffer for biological experiments. The buffer is made by combining H2PO4- pKa = 7.21 and HPO42-.
a) Explain how much KH2PO4 (MW= 136.1 g/mol) and K2HPO4 (174.2 g/mol) would to make 300 ml of 50 mM phosphate buffer at pH 7.35?
b) You then add 8 ml of 1 M HCL to the buffer you made in a), explain what the final pH is after the addition of the acid?
c) You are interested in making 1L of 75mM phosphate buffer pH 7.4. You have a starting solution of 1 M H2PO4- and a 0.5 M solution of HCL. Explain how you would make this buffer.