Consider the following graph,

The above graph represents the change in energy for the reaction, $\mathrm{A}+\mathrm{B}⟶\mathrm{C}+\mathrm{D}.$
Here P is the
 

 

activation energy for the reaction, $\mathrm{A}+\mathrm{B}\to \mathrm{C}+\mathrm{D}$

energy change for the reaction,$\mathrm{A}+\mathrm{B}\to \mathrm{C}+\mathrm{D}$

activation energy for the reaction,$\mathrm{C}+\mathrm{D}\to \mathrm{A}+\mathrm{B}$

energy change for the reaction,$\mathrm{C}+\mathrm{D}\to \mathrm{A}+\mathrm{B}$