Phenolphthalein is a pH indicator. It is colorless in neutral or acidic solutions and turns pink as the pH increases above 8.3.
It can be used to investigate the rate of urea hydrolysis by the enzyme urease.
Samples of urea solution mixed with a small amount of weak acid and phenolphthalein were incubated with urease at different temperatures.
The time taken for the mixture to change from colorless to pink was recorded and used to calculate the rate of reaction.
Explain why the mixture turns from colorless to pink when urease breaks down urea.
