{"knowledge_schema": {"broad_category": "Chemistry \u2192 Acid-Base Chemistry \u2192 pH Calculation", "refinement": "This problem involves calculating the pH of a solution resulting from the dissociation of a salt (Na3PO4) in water, which affects the concentration of hydroxide ions due to hydrolysis.", "specific_scope": "The focus is on the dissociation of Na3PO4 in water, leading to the formation of phosphate ions and their subsequent equilibrium with water, impacting the pH of the solution.", "goal": "Calculate the pH of the resulting solution after dissolving Na3PO4 in water, considering the dissociation constants of phosphoric acid."}, "summary": "This problem is centered on acid-base chemistry, specifically the calculation of pH in a solution formed by dissolving a salt (Na3PO4) in water. The dissociation of Na3PO4 leads to the formation of phosphate ions, which can affect the pH through hydrolysis. The task involves using the dissociation constants of phosphoric acid to determine the equilibrium concentrations of hydroxide ions and subsequently calculate the pH of the solution. The correct answer to the pH calculation is 12.13."}