Why does phenolphthalein turn colorless in strong base, and how does that affect its industrial use?
This fading is not a defect but a useful property in some analytical methods, such as determining carbonate in strongly alkaline solutions. However, for routine quality control, many labs now prefer automated pH meters, reducing the demand for phenolphthalein as a primary indicator. That said, its low cost and visual clarity keep it in school labs and field tests where electronics are impractical.
