Rainbow experiment.
The hydrolysis of t-butyl bromide is visually demonstrated by adding a clear liquid (NaOH) to a red solution (HBr), resulting in a sequence of rainbow colors. Remarkably, the colors then reverse from violet to red after a few seconds. This captivating demonstration employs universal indicator to showcase the hydrolysis reaction of tert-butyl chloride. As the hydrolysis reaction generates HBr acid, it gradually consumes the clear base solution, elevating the pH and revealing the rainbow colors of the universal indicator. Upon complete depletion of the base, the acid concentration increases again, causing the colors to revert to red.

The reaction equation that generates HBr acid in water.