Increasing the concentration of one of the reactants in a chemical reaction at equilibrium will cause the reaction to shift in the direction that consumes the added reactant, according to Le Chatelier's principle. This principle states that if a system at equilibrium is subjected to a change in concentration, temperature, or pressure, the system will adjust itself to counteract the change and restore a new equilibrium.As an example, let's consider the following reversible reaction:N2 g + 3H2 g 2NH3 g This reaction represents the synthesis of ammonia NH3 from nitrogen N2 and hydrogen H2 gases. If we increase the concentration of nitrogen N2 while keeping the concentrations of hydrogen H2 and ammonia NH3 constant, the reaction will shift to the right, towards the formation of more ammonia NH3 . This shift occurs because the system is trying to counteract the increase in nitrogen concentration by consuming the added nitrogen and converting it into ammonia.In summary, increasing the concentration of one of the reactants in a chemical reaction at equilibrium will cause the reaction to shift in the direction that consumes the added reactant, in accordance with Le Chatelier's principle.