Titration curves

[chemmy]

What would the titration curve for the reaction of a diprotic acid and a strong base containing two hydroxide ions look like? Would it have two equivalence points, or just one? For example, if carbonic acid was titrated against barium hydroxide... I know that a titration curve for a diprotic acid and a strong base with one hydroxide like NaOH would have two equivalence points, but what happens when there are two?

[Tartaglia]

It is easier to draw than explain,but there should be four points of inflexion, two near vertical and two near horizontal. Assuming we are adding the strong base to the acid the pattern should go from low to high pH in the following manner

1 A near horizontal point of inflexion (slightly upward sloping) at pKa1

2 A near vertical point of inflexion at first neutralisation point

3 A near horizontal point of inflexion (slightly upward sloping) at pKa2

4 A near vertical point of inflexion at 2nd neutralisation point

 

1 and 3 are called buffering regions

[chemmy]

Thank you! That makes perfect sense

[hermanntrude]

What would the titration curve for the reaction of a diprotic acid and a strong base containing two hydroxide ions look like? Would it have two equivalence points, or just one? For example, if carbonic acid was titrated against barium hydroxide... I know that a titration curve for a diprotic acid and a strong base with one hydroxide like NaOH would have two equivalence points, but what happens when there are two?

 

there are a few websites which will draw a graph of a titration curve based upon data such as Ka and Kb and so on. perhaps that'd be useful for you. Search google for "titration curve" or something like that