{"knowledge_schema": {"broad_category": "Chemistry \u2192 Coordination Chemistry \u2192 Complex Ion Equilibria", "refinement": "This problem involves the dissociation of a metal-ligand complex in solution and the calculation of free metal ion concentration based on equilibrium constants.", "specific_scope": "The focus is on determining the concentration of free magnesium ions in a solution containing a known concentration of the Mg-EDTA complex at a specific pH and temperature.", "goal": "Calculate the concentration of magnesium ions in the solution using the provided equilibrium constant and the concentration of the Mg-EDTA complex."}, "summary": "This problem falls under the category of coordination chemistry, specifically dealing with the equilibria of metal-ligand complexes. It requires calculating the concentration of free magnesium ions in a solution containing a stoichiometric Mg-EDTA complex at a given pH and temperature. By applying the equilibrium constant for the dissociation of the complex, we can determine the concentration of magnesium ions. The answer to the problem is found to be 1.0x10^-6 M."}