{"knowledge_schema": {"broad_category": "Chemistry \u2192 Coordination Chemistry \u2192 Equilibrium Calculations", "refinement": "This problem involves calculating the concentration of free EDTA ions in a solution containing a metal-EDTA complex, considering the equilibrium constant and the pH of the solution.", "specific_scope": "The focus is on the equilibrium between the Ca-EDTA complex and free EDTA ions, taking into account the fraction of EDTA in its deprotonated form at a specific pH.", "goal": "Determine the concentration of free EDTA ions in the solution based on the provided information and equilibrium constant."}, "summary": "This problem is rooted in coordination chemistry and equilibrium calculations, specifically focusing on the dissociation of a metal-EDTA complex in solution. Given the concentration of the Ca-EDTA complex, the equilibrium constant, and the fraction of EDTA in its deprotonated form at a specific pH, the objective is to calculate the concentration of free EDTA ions. This involves applying the equilibrium expression for the dissociation of the complex and using the provided values to find the desired concentration."}