In a second-order reaction, the reaction rate is directly proportional to the square of the concentration of one reactant or the product of the concentrations of two reactants. The rate law for a second-order reaction can be represented as:Rate = k[A]^2 for a reaction with one reactant orRate = k[A][B] for a reaction with two reactants where Rate is the reaction rate, k is the rate constant, and [A] and [B] are the concentrations of the reactants.When the concentration of a reactant in a second-order reaction increases, the reaction rate increases by the square of the change in concentration. For example, if the concentration of a reactant doubles, the reaction rate will increase by a factor of 4 2^2 = 4 . Similarly, if the concentration of a reactant is halved, the reaction rate will decrease by a factor of 1/4 0.5^2 = 0.25 .Experimental evidence for the effect of changes in reactant concentration on the reaction rate for a second-order reaction can be obtained by measuring the reaction rate at different concentrations of the reactants and observing the relationship between the concentration and the reaction rate.One classic example of a second-order reaction is the reaction between iodide ions I- and persulfate ions S2O8^2- in an aqueous solution:2I- + S2O8^2- 2IO3- + 2SO4^2-In this reaction, the rate law is given by:Rate = k[I-][S2O8^2-]To provide experimental evidence for the effect of changes in reactant concentration on the reaction rate, you can perform the following steps:1. Prepare several solutions with varying concentrations of I- and S2O8^2- ions.2. Measure the initial rate of the reaction for each solution. This can be done by monitoring the formation of the product IO3- or the disappearance of the reactants I- or S2O8^2- over time using spectroscopic or other analytical techniques.3. Plot the reaction rate against the concentration of the reactants.4. Analyze the data to determine the relationship between the reaction rate and the concentration of the reactants.If the reaction is indeed second-order, you will observe that the reaction rate increases with the square of the change in concentration of the reactants, confirming the effect of changes in reactant concentration on the reaction rate for a second-order reaction.