Increasing the concentration of reactants in a reaction at equilibrium will cause the reaction to shift in the direction of the products, 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.When the concentration of reactants is increased, the system will respond by consuming more of the reactants to form more products, thus shifting the equilibrium position towards the products. This is done to counteract the change in reactant concentration and re-establish equilibrium. As a result, the rate of the forward reaction will increase, and the rate of the reverse reaction will decrease until a new equilibrium is reached.