The reaction between hydrochloric acid HCl and sodium thiosulfate Na2S2O3 can be represented by the following balanced chemical equation:2HCl + Na2S2O3 2NaCl + H2O + SO2 + SIn this reaction, hydrochloric acid reacts with sodium thiosulfate to produce sodium chloride, water, sulfur dioxide, and solid sulfur. The reaction rate and yield are affected by the initial concentration of the reactants, as described below:1. Reaction rate: The reaction rate is directly proportional to the concentration of the reactants. According to the collision theory, increasing the concentration of the reactants increases the number of particles in the reaction mixture. This leads to a higher frequency of collisions between the reacting particles, resulting in an increased reaction rate. Therefore, if the initial concentration of either hydrochloric acid or sodium thiosulfate is increased, the reaction rate will also increase.2. Reaction yield: The reaction yield refers to the amount of product s formed in a chemical reaction. In the case of the reaction between hydrochloric acid and sodium thiosulfate, the reaction goes to completion, meaning that all of the limiting reactant will be consumed, and no reactant will be left in the reaction mixture. The yield of the reaction depends on the stoichiometry of the reactants and the limiting reactant.If the initial concentrations of both reactants are increased equally, the yield of the products will also increase, as there will be more reactants available to form products. However, if the initial concentration of one reactant is increased while the other remains constant, the yield of the products will still be determined by the limiting reactant. In this case, increasing the concentration of the non-limiting reactant will not affect the yield of the products.In summary, increasing the initial concentration of the reactants in the reaction between hydrochloric acid and sodium thiosulfate will increase the reaction rate, while the yield of the products will depend on the stoichiometry of the reactants and the limiting reactant.