Final answer:
The reaction rate is expected to decrease when the dye concentration is half of the concentration in the original question.
Step-by-step explanation:
The reaction rate is expected to decrease when the dye concentration is half of the concentration in the original question. This is because the rate of a reaction is directly proportional to the concentration of the reactant. When the concentration is halved, there are fewer reactant particles available for collisions, resulting in a slower reaction rate.