For a reversible reaction \( A \rightleftharpoons B \), the \( \Delta H_{\text{forward reaction}} = 20 \,\text{kJ mol}^{-1} \). The activation energy of the uncatalyzed forward reaction is \( 300 \,\text{kJ mol}^{-1} \). When the reaction is catalysed keeping the reactant concentration same, the rate of the catalysed forward reaction at \( 27^\circ \text{C} \) is found to be same as that of the uncatalyzed reaction at \( 327^\circ \text{C} \). The activation energy of the catalysed backward reaction is ________ \( \text{kJ mol}^{-1} \).
