When water is added to t-butyl chloride the timer is started. An indicator that changes color when the solution contains hydrochloric acid has been added to the t-butyl chloride. During the reaction the water displaces the chloride and forms t-butyl alcohol and hydrochloric acid. After 2 minutes and 41 seconds, the reaction has progressed to the point where enough hydrochloric acid has been produced to change the color of the solution. When the same reaction is carried out with trimethyl silyl chloride the reaction occurs immediately.