Chapter 18, Problem 80E

Phenolphthalein has a pK_aof 9.7. It is colorless ¡n its acid form and pink in its basic form. For each of the pH values, calculate $[{\text{In}}^{-}]/[\text{HIn]}$ and predict the color of a phenolphthalein solution.

$\text{pH = 2}\text{.0}$
$\text{pH = 5}\text{.0}$
$\text{pH = 8}\text{.0}$
$\text{pH = 11}\text{.0}$