Part A: Thymolphthalein is an indicator that changes color over a range from pH = 9.3 to pH = 10.5 . What is Ka of thymolphthalein? Part B: Alizarin yellow R, Ka=7.9x10^-12, is yellow in its protonated form (HX) and red in its ionized form (X-). At what pH will alizarin yellow R be a perfect orange color?