In the graph above the activation energy of the... - JAMB Chemistry 2013 Question

The activation energy of a catalyzed reaction is the energy difference between the reactants and the highest point on the energy profile when a catalyst is present. In the graph, the activation energy for the catalyzed reaction is the energy difference between the reactants (at 100 kJ) and the peak of the catalyzed reaction (at 300 kJ). Therefore, Activation Energy = 300 kJ - 100 kJ = 200 kJ.