49.0 MB (3.9 MB compressed)
5087 x 3367 pixels
43.2 x 28.4 cm ⏐ 17.0 x 11.2 in (300dpi)
GIPHOTOSTOCK / SCIENCE PHOTO LIBRARY GIPHOTOSTOCK / SCIENCE PHOTO LIBRARY
Phenolphthalein indicator. Phenolphthalein indicator solution added to several test tubes containing sodium hydroxide solutions with varying pH values, left to right: pH = 8, 9, 10, 11, 12, 13. Phenolphthalein changes its colour depending on the pH of the solution. In acidic solutions it is colourless while in basic solutions it turns into a pinkish violet (fuchsia) colour.
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