What pH is needed for a buffer to achieve a Mg2+ concentration of 3.0 × 10^-2 M in equilibrium with solid magnesium oxalate?

Verified step by step guidance

1. Identify the relevant chemical equilibrium: The dissolution of magnesium oxalate, MgC2O4, in water can be represented by the equation: MgC2O4(s) \rightleftharpoons Mg^{2+}(aq) + C2O4^{2-}(aq).
2. Use the solubility product constant (K_sp) for magnesium oxalate: The K_sp expression is K_{sp} = [Mg^{2+}][C2O4^{2-}]. You will need the K_sp value for magnesium oxalate from a reference source.
3. Relate the pH to the concentration of oxalate ions: The oxalate ion (C2O4^{2-}) is the conjugate base of oxalic acid (H2C2O4). The pH will affect the concentration of C2O4^{2-} through the acid dissociation equilibria of oxalic acid.
4. Set up the equilibrium expression: Substitute the given [Mg^{2+}] = 3.0 \times 10^{-2} M into the K_sp expression to solve for [C2O4^{2-}].
5. Determine the pH: Use the relationship between [C2O4^{2-}] and the pH, considering the dissociation constants (K_a1 and K_a2) of oxalic acid, to find the pH that results in the calculated [C2O4^{2-}].