Changing the stoichiometric ratio of reactants in a chemical reaction can affect the reaction rate in several ways. In the case of the reaction between an acid and calcium carbonate, the reaction can be represented by the following balanced equation:CaCO3 s + 2H+ aq Ca2+ aq + CO2 g + H2O l Here, calcium carbonate CaCO3 reacts with an acid H+ to produce calcium ions Ca2+ , carbon dioxide CO2 , and water H2O . The stoichiometric ratio of reactants in this balanced equation is 1:2, meaning that one mole of calcium carbonate reacts with two moles of acid.If the stoichiometric ratio of reactants is changed, the reaction rate can be affected in the following ways:1. If there is an excess of acid H+ , the reaction rate may increase initially because there are more acid molecules available to react with the calcium carbonate. However, once the calcium carbonate is completely consumed, the reaction will stop, and any excess acid will remain unreacted.2. If there is a deficiency of acid H+ , the reaction rate may decrease because there are fewer acid molecules available to react with the calcium carbonate. In this case, the reaction will stop before all the calcium carbonate is consumed, and some calcium carbonate will remain unreacted.3. If the stoichiometric ratio of reactants is maintained 1:2 , the reaction rate will be optimal because all the reactants will be consumed, and the reaction will proceed to completion.It is important to note that other factors, such as temperature, pressure, and the presence of catalysts, can also affect the reaction rate. However, changing the stoichiometric ratio of reactants can have a significant impact on the reaction rate by altering the availability of reactants for the reaction to proceed.