For the second-order reaction A+B?Products, the rate of reaction r, may be written as
r= dx/dt=k([A] 0 -X) ([B] 0 +X)
X is the decrease in concentration of A or B as a result of the reaction. What are the condition for the rate to be a maximum for the rate to be a maximum or a minimum? Draw a graph of r against X, and noting that r and X can not to be negative, identify the portion of curve that corresponds to reality.