In a second-order chemical reaction, the reaction rate is directly proportional to the concentration of each reactant raised to the power of 2. The rate law for a second-order reaction can be represented as:Rate = k[A]^2 or Rate = k[A][B]where Rate is the reaction rate, k is the rate constant, [A] and [B] are the concentrations of the reactants, and the exponents represent the order of the reaction with respect to each reactant.If the concentration of one reactant is changed, the overall reaction rate will be affected. For example, if the concentration of reactant A is doubled, the reaction rate will increase by a factor of 4 2^2 = 4 for a reaction with rate law Rate = k[A]^2. If the reaction follows the rate law Rate = k[A][B], and the concentration of reactant A is doubled, the reaction rate will double as well.In summary, changing the concentration of one reactant in a second-order chemical reaction will have a significant effect on the overall reaction rate. The exact effect depends on the rate law and the specific change in concentration.