Question

Acid + Base → Turns phenolphthalein pink
More has to be added to make the resulting solution colourless.

• A. acid
• B. base
• C. salt

Answer 1

The correct option is A acid

Phenolphthalein remains colourless in acidic/neutral medium and turns pink in basic medium.
The resulting solution is basic in nature, and thus, more acid has to be added so as to change the colour from pink to colourless.