Question

What will be the observation when a few drops of phenolphthalein indicator are added to an alkaline solution?

• A. Colour of phenolphthalein remains unchanged.
• B. Colour of phenolphthalein changes to yellow.
• C. Colour of phenolphthalein changes to blue.
• D. Colour of phenolphthalein changes to pink.

Answer 1

The correct option is D Colour of phenolphthalein changes to pink.

Phenolphthalein is a synthetic indicator used to detect the acidic or basic (alkaline) nature of a solution. It remains colourless in an acidic solution and turns pink in a basic (alkaline) solution.