In the presence of a catalyst,the heat evolved or absorbed during the reaction . . . . . . .

For the following two reactions,which statement is true?

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

Draw an energy profile diagram for a three-step reaction in which the first step is the slowest and the last step is the fastest. (Assume that the reaction is exothermic)

The correct reaction profile diagram for a positive catalyst reaction.

$A$ reaction having equal energies of activation for forward and reverse reactions has