4) You wish to make a buffer with a pH of 4.72 using 100.0mL of a 1.00M solution of hydrazidic acid, HN3 - Which of the following could you add to make a buffer system? A) Hydrochloric acid, HCl B) Sodium hydroxide, NaOH C) Water, H2O D) Ammonia, NH3 - How many moles do you need to add to form the desired buffer? razidic acid =HN3,pKs=4.72