Please only answer part b and part c based on the pKa values given in part a. It's really important pls show the details

a. Phosphate is a buffer with three ionizable groups, of pka values 2.2, 7.2 and 12.3. Draw the chemical equilibrium for each of the different species and indicate each transition with the respective pka value. b. You want to prepare 500 ml of a 20 mM phosphate buffer at pH 6. First, you prepare a 1M stock solution of NaH2PO4 and dilute it to give a final phosphate concentration of 20mM. What is the pH of this solution? How much volume of a 1M NaOH solution do you need to add to adjust the pH to 6? For the pka values of phosphate see b, above. c. You are not happy with the volume increase and dilution of actual phosphate concentration from your first approach in b. You therefore now decide to prepare the 500 ml of a 20 mM phosphate buffer at pH 6 from a 1M stock solution of NaH2PO, and a 1M stock solution of Na2HPO4 instead. How much of each stock solution do you need to combine with water to obtain the desired pH of 6.0