An aqueous solution of reactant A with initial concentration CAo is charged into a batch reactor. The reactant A undergoes the following series reactions in which the second reaction is reversible: k1 k2 A R S k3 (a) Derive the expression for concentration of R, CR, as a function of time, t. (15 marks) (b) Hence, obtain the expression for the reaction time, tmax, at which maximum concentration of R occurs in the batch reactor. (10 marks)