Changing the concentration of reactants can significantly affect the selectivity of a chemical reaction with multiple possible products. The selectivity of a reaction refers to the preference for the formation of one product over another. There are several ways in which changing reactant concentrations can influence selectivity:1. Le Chatelier's Principle: According to Le Chatelier's principle, if a system at equilibrium is subjected to a change in concentration, the system will adjust to counteract the change and restore equilibrium. If increasing the concentration of a reactant favors the formation of a particular product, the reaction will shift towards that product, increasing its selectivity.2. Reaction kinetics: The rate at which different products are formed can be influenced by the concentration of reactants. Some reactions may have faster rates at higher concentrations, while others may have slower rates. If the rate of formation of one product is more sensitive to concentration changes than another, altering the concentration of reactants can change the selectivity of the reaction.3. Reaction pathways: In some cases, changing the concentration of reactants can alter the reaction pathway, leading to the formation of different products. This can occur if a reaction has multiple intermediate steps, and the concentration of reactants affects the stability or reactivity of these intermediates.4. Catalysts and inhibitors: The presence of catalysts or inhibitors can also affect the selectivity of a reaction. Changing the concentration of reactants may alter the effectiveness of these species, leading to changes in product selectivity.5. Competitive reactions: In some cases, multiple reactions may compete for the same reactants. If the concentration of one reactant is increased, it may outcompete other reactions, leading to a change in product selectivity.In summary, changing the concentration of reactants can have a significant impact on the selectivity of a chemical reaction with multiple possible products. The specific effect will depend on the reaction system and the nature of the reactants and products involved.