Ferroin is used as this species in the Belousov–Zhabotinsky reaction. Calcein (“CAL-see-in”) and (20[1])eriochromes (“AIR-ee-oh-chromes”) are used as these species in trace metal analysis because they are worse chelators (“KEY-laters”) than EDTA. Chemists use natural (0[1])anthocyanins (0[1])as these species. (20[1]0[1])Volumetric analysis adds these (0[1])chemicals (20[1])at conventionally (20[1])imprecise volumes (20[1]0[1])like “two drops.” (20[2])By forming a charge-transfer complex, (20[2])starch (20[1])acts as this species when (0[2])(*) iodine (10[2])and thiosulfate react. (10[2]0[1])These chemicals first undergo a reaction (10[1])at the endpoint, just past (10[2])the equivalence point, to form (10[1])a chromophore. (10[3])A mixture of these molecules like methyl red and phenolphthalein (10[2]0[1])(“FEEN-ol-FAY-leen”) is impregnated (10[2])into paper strips to test a solution’s pH. (10[1])For 10 points, name these chemicals that change color in a titration. (10[5])■END■ (10[3]0[1])