Question

Observe the statements. I. Phenolphthalein is a colourless solution II. Phenolphthalein turns pink in basic solution III. Phenolphthalein turns red in acidic solution IV. Phenolphthalein remains colourless in acidic solution Choose the correct option a.I &II are correct b.I & III are correct c.I ,II & IV are correct d.All the statements are correct

Answer 1

c.I ,II & IV are correct

Step-by-step explanation:

Phenolphthalein is an indicator. An indicator is an organic dye whose solution changes colour as the concentration of hydrogen ions in solution changes.

Hence a typical indicator exhibits different colours at different pH ranges. The colour of an indicator in an acid, a base and at end point always differs.

Phenolphthalein is a colourless solution which has a pink colour in an alkaline medium and colourless in an acidic medium.