Question

What would be the reason for phenolphthalein used as an indicator to distinguish between acid and alkali

Answer 1

Answer:

phenolphthalein is a very good indicator to distinguish between acid and alkali because it has colour changing properties in presence of these substances.

phenolphthalein becomes pink in presence of base where as it becomes colourless in presence of an acid.

it is also used in case of titration in order to accurately determine the concentration of an acid or a base

Answer 2

AnSwEr:

$\longrightarrow$Phenolphthalein is another commonly used indicator for titrations, and is another weak acid. Adding extra hydrogen ions shifts the position of equilibrium to the left, and turns the indicator colourless.