[Solved] If 3 mL of 0.1 M tBuCl in acetone is mixed with 0.9 mL of 0.1 M of NaOH and

If 3 mL of 0.1 M tBuCl in acetone is mixed with 0.9 mL of 0.1 M of NaOH and 6.1 mL of water and it takes 360 seconds for the color of the added bromophenol blue indicator to change from blue to yellow, what does this indicate