{"knowledge_schema": {"broad_category": "Chemistry \u2192 Coordination Chemistry \u2192 Complex Ion Equilibria", "refinement": "This problem involves the dissociation of a metal complex in solution and the calculation of ion concentrations based on equilibrium constants.", "specific_scope": "The focus is on determining the concentration of free calcium ions in a solution containing a known concentration of the Ca-EDTA complex, using the stability constant (K) for the complex.", "goal": "Calculate the concentration of free calcium ions (Ca\u00b2\u207a) in the solution based on the provided concentration of the Ca-EDTA complex and the stability constant."}, "summary": "This problem is rooted in coordination chemistry, specifically dealing with the dissociation of metal complexes in solution. It requires calculating the concentration of free calcium ions from a known concentration of the Ca-EDTA complex and the stability constant (KCa-EDTA). The goal is to find the concentration of calcium ions in the solution, which involves applying the equilibrium expression related to the stability constant."}