Final answer:
The rate of association for the reaction A + B → AB is given by the rate law rate = k [A] [B], signifying it is directly proportional to the concentrations of both reactants and it is a second-order reaction.
Step-by-step explanation:
The rate of association concerning the reaction A + B → AB is determined by the rate at which molecules A and B collide and form the product AB. This reaction is first order with respect to each reactant A and B, meaning that each reactant's concentration has a direct impact on the rate of the reaction. Hence, the rate law for this reaction, considering it is a second-order overall (first order in A and B respectively), is expressed as rate = k [A] [B], where k is the specific rate constant of the reaction.
For a reaction of this nature, if you were to double the concentration of A alone, the reaction rate would also double. The same holds true if you double the concentration of B alone. This is because the likelihood of productive collisions between reactant molecules increases proportionally with their concentrations, as predicted by the Law of Mass Action.