Consider the following heterogeneous catalytic reaction scheme in which gaseous benzene (A) adsorbs on a catalyst surface and undergoes an irreversible reaction with non-adsorbed gas propylene (B) to produce cumene (C), which subsequently desorbs: Reaction 1 (adsorption of A): A+()K1k2K1(A) Rection 2 (surface reaction): (A)+Bk2(C) Reaction 3 (desorption of C): (C) k3k3( ) + C The surface reaction is the rate controlling step. The reaction is carried out in a differential reactor to which A,B and C are all fed. (a) Show that the rate expression may be written in terms of partial pressures of components: r=1+kAPA+kCPCkPAPB and obtain expressions for k,kA, and kcc. All the symbols represent the usual parameters. [10 marks]