Weak acids or bases {indicator, acidity}| with conjugated double bonds can change electronic structure and color at different pH. At pH 1, malachite green changes from yellow to green. At pH 2, thymol blue changes from red to yellow. At pH 4, bromphenol blue changes from yellow to blue. At pH 4, methyl orange changes from red to yellow. At pH 4.5, bromcresol green changes from yellow to blue. At pH 5, methyl red changes from red to yellow. At pH 7, bromthymol blue changes from yellow to purple. At pH 7.4, phenol red changes from yellow to red. At pH 9, phenolphthalein changes from clear to red. At pH 9, thymol blue changes from yellow to blue. At pH 10, thymolphthalein changes from clear to blue. At pH 11, alizarin yellow R changes from yellow to red.
Physical Sciences>Chemistry>Inorganic>Acid-Base
5-Chemistry-Inorganic-Acid-Base
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Date Modified: 2022.0224