Suppose you have four test tubes labelled A B C and D A contains water B contains solution of an alk...........

General Science (NDA) Chemistry

Suppose you have four test tubes labelled A, B, C and D. A contains water, B contains solution of an alkali, C contains solution of an acid, and D contains solution of sodium chloride. Which one of these solutions will turn phenolphthalein solution pink?

Solution A

Solution B

Solution C

Solution D

Explanation:

Solution B, i.e. solution of an alkali will turn phenolphthalein solution pink because phenolphthalein is a weak organic acid. It turns colourless in acidic solution and pink in basic solution. It is a synthetic indicator used in acid-base titrations.