The energies of activation for forward and reverse reaction for A2+B2⇌2AB are 180 kJ mol−1 and 200 kJ mol−1 respectively. The presence of catalyst lowers the activation energy of both (forward and reverse) reactions by 100 kJ mol−1. The enthalpy change of the reaction (A2+B2→2AB) in the presence of catalyst will be (in kJ mol−1):