Question

Phenolphthalein is used as an indicator for basic solutions in the electrolytic cell that's used to split water into its elements. Around which electrode would the solution turn pink?

Answer 1

Answer:

Anode

Explanation:

In the electrolysis of acidified water;

Anode half reaction;

4OH^-(aq)-----> 2H2O(l) + O2(g) + 4e

Cathode half reaction;

4H^+(aq) + 4e ----> 2H2(g)

Phenolphthalein has a pink colour in a neutral medium. A neutral medium in this electrolysis is one in which the hydroxide ion is reduced to water and oxygen and this occurs at the anode hence this is the electrode around which the solution will turn pink.