A first order gaseous phase reaction is catalysed by a non-porous solid. The kinetic rate constant and the external mass transfer co-efficients are k and kg respectively. The effective rate constant (keff) is given by________________?

Question

Accepted Answer

1/keff = 1/k + 1/kg. When both reaction kinetics and external mass transfer limit the rate, the overall rate constant is determined by the sum of the resistances in series. This leads to the reciprocal relationship shown.