Adding a known concentration of a specific reaction intermediate to a chemical reaction can affect the rate of the reaction in several ways, depending on the nature of the reaction and the intermediate itself. The mechanism behind this observed effect can be explained through the principles of chemical kinetics and the role of reaction intermediates in the reaction mechanism.1. Increase in reaction rate: In some cases, adding a reaction intermediate can increase the rate of the reaction. This is because the intermediate can act as a catalyst, lowering the activation energy required for the reaction to proceed. By providing an alternative reaction pathway with a lower activation energy, the reaction rate increases as more reactant molecules have sufficient energy to overcome the activation energy barrier.2. Decrease in reaction rate: In other cases, adding a reaction intermediate can decrease the rate of the reaction. This can occur if the intermediate reacts with one of the reactants or products, forming a new species that is less reactive or forms a stable complex. This would effectively decrease the concentration of the reactant or product involved in the rate-determining step, leading to a slower reaction rate.3. No effect on reaction rate: In some cases, adding a reaction intermediate may not have any significant effect on the reaction rate. This can happen if the intermediate is not involved in the rate-determining step of the reaction or if its presence does not alter the activation energy barrier.The specific effect of adding a reaction intermediate on the rate of a chemical reaction depends on the reaction mechanism and the role of the intermediate in that mechanism. By understanding the reaction mechanism and the role of intermediates, chemists can manipulate reaction conditions to control reaction rates and optimize chemical processes.