The rate expression for a heterogenous catalytic reaction is given by, - r<sub>A</sub> = K.K<sub>A</sub> P<sub>A</sub>(1 + K<sub>A</sub>.P<sub>A</sub> + K<sub>r</sub>.P<sub>R</sub>), where K is surface reaction rate constant and K<sub>A</sub> and K<sub>R</sub> are absorption equilibrium constants of A and R respectively. If K<sub>R</sub> P<sub>R</sub> &gt;&gt; (1 + K<sub>A</sub> P<sub>A</sub>), the apparent activation energy E<sub>A</sub> is equal to (given E is the activation energy for the reaction and ΔH<sub>R</sub> and ΔH<sub>A</sub> are the activation energies of adsorption of R and A)

Correct Answer: E + ΔH<sub>A</sub> - ΔH<sub>R</sub>