Question

An unknown solution changed the color of a phenolphthalein indicator from colorless to pink. What would you comment about the pH of the unknown solution? A. The given solution is acidic in nature. B. The given solution is basic in nature. C. The given solution is neutral in nature.

Answer 1

Answer : The correct option is, (A) The given solution is basic in nature.

Explanation :

Indicators : It is a substance that gives the visible sign by the color change of the chemical species like an acid or a base.

Phenolphthalein, methyl orange, methyl red, etc are the type of acid-base indicators which changes the color based on pH values. They are used in the acid-base titration.

The given indicator is, Phenolphthalein.

The role of phenolphthalein indicator is that it imparts pink color to an alkaline or basic solution and it is colorless in acidic solution.

From the given problem, we conclude that the unknown solution (given solution) is, basic in nature that changes the color of a phenolphthalein indicator from colorless to pink.

Hence, the correct option is, (A) The given solution is basic in nature.

Answer 2

I think the correct answer from the choices listed above is option B. An unknown solution changed the color of a phenolphthalein indicator from colorless to pink. The given solution would be basic in nature. Phenolphthalein indicator is commonly used in acid-base titrations where it changes from colorless when acidic to pink when basic.