Phosphate buffer is a commonly used buffer for biological experiments. The buffer is made by combining H2PO4- (pKa = 7.21) and HPO42-.
a) How much KH2PO4 (MW= 136.1 g/mol) and K2HPO4 (174.2 g/mol) would you need 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), what is the final pH after the addition of the acid?
c) You are interested in making 1L of 75 mM phosphate buffer pH 7.4. You have a starting solution of 1 M H2PO4- and a 0.5 M solution of HCl. Describe
how you would make this buffer.