The energies of activation for forward and reverse reactions for  $A_2+B_2\rightleftharpoons 2AB$ are $180kJmo{l}^{-1}$  and  $200kJmo{l}^{-1}$ respectively. The presence of a catalyst lowers the activation energy of both (forward and reverse) reactions by $100kJmo{l}^{-1}$ . The enthalpy change (Magnitude only)of the reaction  $\left(A_2+B_2\to 2AB\right)$ in the presence of a catalyst will be (in kJ  $mo{l}^{-1}$)