Malonic acid (H2M) is a diprotic acid. You wish to prepare abuffer of malonic acid (pKa1 = 2.847, pKa2= 5.696) with a final pHof 2.90 but you only have disodium malonate (M2-) in yourlaboratory shelf. You dissolve 100 mmol of this salt in 1 L ofwater. Assume both dissociation processes are decoupled.
What is the initial pH of the solution? State any assumptionsyou make.
How many equivalents of strong acid must you add to yoursolution to end with only HM- ?
What is the approximate pH of this solution of HM- ? Use anadequate mathematical approximation.
How many additional equivalents must you add to reach thedesired pH of 2.90?
