Pyrophosphate (P₂O₇⁴⁻) is added to laundry detergents to prevent the precipitation of insoluble calcium and magnesium salts. Consider a scenario where Na₂H₂P₂O₇ is added to the solution and we're trying to dissolve Ca(OH)₂ salts because Ca²⁺ ions form a soluble complex with pyrophosphate.

(a) Given that the K_sp for Ca(OH)₂ is 4.7×10^–6 and the K_f for [Ca(P₂O₇)]²⁻ is 4.0×10⁴, determine the equilibrium constant (K_eq) for the reaction.

(b) What is the molar solubility of Ca(OH)₂ in 2.50 M Na₂H₂P₂O₇ solution?

[K_a2 H₂P₂O₇^2– = 2.51×10^–7; K_a3 HP₂O₇^3– = 3.89×10^–10]