Reaction Rate: The rate at which a reaction proceeds can be heavily dependent on the concentration of reactants. Optimal ratios can maximize the reaction rate, leading to faster production. Product Yield: The amount of desired product formed can vary with different reactant ratios. Balancing these ratios can maximize yield and minimize by-products. Selectivity: In many catalytic processes, multiple products are possible. Proper reactant ratios can enhance the selectivity towards the desired product, thus improving process efficiency.