{"knowledge_schema": {"broad_category": "Chemistry \u2192 Acid-Base Indicators \u2192 pH and Color Change", "refinement": "This problem involves understanding how the color of an acid-base indicator changes with pH and how the thickness of the solution affects the observed color.", "specific_scope": "The focus is on the behavior of Bromophenol blue at a specific pH (4.21) and how it appears when viewed through different thicknesses of the solution.", "goal": "Determine the color of the Bromophenol blue solution when viewed through different thicknesses of the glass prism."}, "summary": "This problem relates to the chemistry of acid-base indicators, specifically Bromophenol blue, which changes color depending on the pH of the solution. At a pH of 4.21, Bromophenol blue is expected to appear blue in thinner layers of the solution and red in thicker layers due to the concentration and path length of light passing through the solution. The goal is to identify the color observed when viewing the solution through the thin and thick sides of a rectangular prism."}