An exothermic reaction `XrarrY` has an activation energy of `90kJ mol^(-1)` of `X` and the heat of reaction is `250 kJ`. Find the activation energy of the reaction `YrarrX`.

Explanation

Since the reaction is exothermic, `E_(a(P)) gt E_(a(r ))`, so the activation energy diagram will be as shown in Figure below.
Energy of activation for the reaction: `Y-X`
`E_(a(p)) = E_(a(r )) + Delta H = 90 + 250 = 340 kJ`
Remember that for reaction with
`n_(p) = n_(r )(Delta H = Delta U)`

Activation energy diagram for the given problem