Use Le Châtelier's principle to explain how adjusting the pH enables the control of C2O42- in a solution of oxalic acid, H2C2O4. Select all that apply:
Increasing the pH shifts the equilibrium and increases the concentration of C2O42-.
Increasing the pH shifts the equilibrium and decreases the concentration of C2O42-.
Decreasing the pH shifts the equilibrium and decreases the concentration of C2O42-.
Decreasing the pH shifts the equilibrium and increases the concentration of C2O42-.