Answer is: a) in the presence of a base.
Phenolphthalein is colorless in acidic solutions and pink in basic solutions.
Acid-base indicators are usually weak acids or bases and they are chemical detectors for hydrogen or hydronium cations.
Example for acid-base indicator is phenolphthalein (molecular formula C₂₀H₁₄O₄).
When solution turns phenolphthalein pink, it means it is basic (pH>7).
The reaction would produce bubbles of gas.
We can prepare 3-5 test tubes of acid with increasing concentrations. Then, we add antacid tablets to each and note the time taken for the tablet to dissolve and stop producing bubbles. The lesser the time taken, the greater the rate of reaction.
When’s I would like to say that it may be B because
