Changing the concentration of reactants in a chemical reaction, such as the reaction between sodium thiosulfate Na2S2O3 and hydrochloric acid HCl , can significantly affect both the reaction rate and the resulting yield.1. Reaction rate: The reaction rate is the speed at which reactants are converted into products in a chemical reaction. According to the collision theory, the reaction rate is directly proportional to the frequency of effective collisions between reactant molecules. When the concentration of reactants is increased, there are more reactant molecules in the same volume, leading to a higher probability of collisions between the molecules. As a result, the reaction rate increases.In the case of the reaction between sodium thiosulfate and hydrochloric acid, which produces sulfur S , sodium chloride NaCl , and water H2O as products:Na2S2O3 aq + 2HCl aq S s + 2NaCl aq + H2O l + SO2 g Increasing the concentration of either sodium thiosulfate or hydrochloric acid will increase the reaction rate, as there will be more effective collisions between the reactant molecules.2. Resulting yield: The yield of a chemical reaction is the amount of product formed, usually expressed as a percentage of the theoretical maximum amount that could be produced based on the stoichiometry of the reaction. In general, increasing the concentration of reactants can lead to a higher yield, as there are more reactant molecules available to form products.However, it is important to note that the yield can also be affected by other factors, such as the presence of side reactions, the reaction conditions e.g., temperature, pressure , and the equilibrium state of the reaction. In the case of the reaction between sodium thiosulfate and hydrochloric acid, the yield is typically high, as the reaction goes to completion and there are no significant side reactions.In summary, increasing the concentration of reactants in the reaction between sodium thiosulfate and hydrochloric acid will generally lead to an increased reaction rate and a higher yield, as there are more reactant molecules available for effective collisions and product formation. However, it is essential to consider other factors that may also influence the yield and reaction rate, such as reaction conditions and the presence of side reactions.