The most common buffer in mammalian tissue culture is aphosphate buffer. The three pKa's of phosphoric acid are 2.16,7.21, 12.32, respectively.
A) For cells to grow normally, the pH must be kept at thephysiological pH of 7.40. Starting with 100.0mL of 0.100M sodiumdihydrogen phosphate, how many mL of 0.100M NaOH must be added toget to physiological pH?
B) What are the concentrations of all species at physiologicalpH?
C) You want to make the buffer but you find you are out ofsodium dihydrogen phosphate so you must start with phosphoric acid.What is the pH of the solution if you add 1.524g of phosphoric acidto enough water to make 100.0mL of solution?
D) How much NaOH must you add to the solution from Part C toget to physiological pH? What is the new total volume?
E) Wouldn't you know it, when you go to the reagent shelf, youfind you are also out of phosphoric acid but at least there is somesodium phosphate. You add 1.882g of sodium phosphate to enoughwater to make 500.0mL of solution. What is the starting pH?