Problem: pH ranges for common acid-base indicators. Most indicators have a useful range of about 2 pH units.If a colorless solution turns pink when we add phenolphthalein, what can we conclude about the pH of the solution?

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Methyl violet has a pH range of 0 to 1.4 with a color range of yellow to violet.  Thymol blue has a pH range of 1 to 2.8 and 8 to 9.5 with a color range of red to yellow and yellow to blue.  Methyl orange has a pH range of 3 to 4.3 and a color range of red to yellow.  Methyl red has a pH range of 4.5 to 6 and a color range of red to yellow.  Bromothymol blue has a pH range of 6 to 7.5 and a color range of yellow to blue.  Phenolphthalein has a pH range of 8 to 10 and a color range of colorless to pink.  Alizarin yellow has a pH range of 10 to12 and a color range of yellow to red.
pH ranges for common acid-base indicators. Most indicators have a useful range of about 2 pH units.

If a colorless solution turns pink when we add phenolphthalein, what can we conclude about the pH of the solution?

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