酚酞是最重要的酸碱指示剂之一。自1871年被合成以来,在分析化学中得到厂泛的应用。其分子结构式如下:酚酞在弱酸性及中性水溶液中无色,在弱碱性溶液中呈紫红色,酚酞的变色间隔为oH 8—10。进一步的试验指出,在强碱性溶液中酚酞的紫红色褪去,溶液无 Phenolphthalein is one of the most important acid-base indicators. Since its synthesis in 1871, it has been widely used in analytical chemistry. Its molecular structure is as follows: phenolphthalein in weakly acidic and neutral aqueous solution colorless, weakly alkaline solution was purple, phenolphthalein discoloration interval oH8-10. Further tests pointed out that in strong alkaline solution of purple phenolphthalein faded solution no