What is the chemistry and the pH of the resulting solution if you mix 750 mL of phthalic acid with dipotassium?

Jason: What is the chemistry and the pH of the resulting solution if you mix 750 mL of phthalic acid with dipotassium?
What is the chemistry and the pH of the resulting solution if you mix 750 mL of phthalic acid with dipotassium phthalate?

There is a limiting reagent and one of the Ka values for either reagent will be used?
The concentration of the phthalic acid is 0.05M and you start with 49.0 grams of dipotassium phthalate.

Answers and Views:

Answer by shalleep
So, you have two equilibrium reactions here, where (A–) is the phthalate….
H2A (phthalic acid) <-----> (HA-) + (H+)
with pKa of 2.92
and

(HA-) <----> (A–) + (H+)
with pKa of 5.41

If you start with 750 mL of phthalic acid, you are looking mostly at that first equilibrium.
THen, if you add potassium phthalate (A–), you shift that second equilibrium to the left to make more HA-. (the potassium is just a spectator ion and doesn’t do anything.

Can’t calculate pH without knowing concentration of phthalic acid and the amount of dipotassium phthalate.
.