複選題

20. A patient with kidney stones is prescribed a citrate-rich drink to help reduce calcium oxalate precipitation in the urinary tract. Considering the solubility of calcium oxalate ($\mathrm{CaC_2O_4}$), which of the following statements are NOT true regarding how pH affects its solubility and the equilibrium involved?
(A) Lowering the pH increases the solubility of calcium oxalate by protonating the oxalate ion ($\mathrm{C_2O_4^{2-}}$).
(B) The solubility equilibrium includes both the Ksp expression and the acid-base equilibrium of oxalate.
(C) Raising the pH causes calcium oxalate to dissolve more readily due to increased $\mathrm{OH}^-$ concentration.
(D) Adding EDTA can shift the dissolution equilibrium toward more dissolved ions.
(E) The mass balance expression: $$ [\mathrm{Ca^{2+}}] = [\mathrm{C_2O_4^{2-}}] - [\mathrm{HC_2O_4^-}] + [\mathrm{H_2C_2O_4}] = \text{solubility} $$