Question

Paheli took dilute Hydrochloric Acid in a test tube and added a few drops of phenolphthalein in it. She observed no change in the colour. But as she put a few drops of Sodium Hydroxide into the solution, it turned pink. Further, when she again put a few drops of the acid the pink colour disappeared. What caused the colour to disappear from the solution?

Answer 1

Answer:

phenolphthalein is act as an indicator which is used to test acidic and basic substance phenolphthalein shows pink colour in basic solution and in acidic solution it shows no colour so when paheli took phenolphthalein in dilute hydrochloric acid it shows that the solution is acidic because it shows no change in colour but when paheli add few drops of phenolphthalein is sodium hydroxide solution it shows that the solution is basic because it changes its colour from colourless solution to pink colour

Answer 2

Explanation:

sodium hydroxide is a base and hydrochloride acid is acidic

so when a phenolphthalein is added to a base it turns pink but when added to acid it it is colourless that's the reason

actually when solution is acidic there will be no colour change and when solution is basic it turns into pink so

when hydrochloric acid is added there is no colourless because it is a acid but when sodium hydroxide is added it turns into pink because it is a base and if you further at hydrochloric acid the colour disappears because there is more amount of hydrochloric acid in the solution

hope it helps you