Question
For an endothermic reaction, energy of activation is Ea and enthalpy of reaction is ΔH (both of these in kJ/mol). Minimum value of Ea will be
-
less than ΔH
-
equal to ΔH
-
more than ΔH
-
equal to zero
Solution
C.
more than ΔH
In endothermic reactions, the energy of reactants is less than that of the products. Potential energy diagram for endothermic reactions is,
Where Ea = activation energy of forwarding reaction
Ea' = activation energy of backwards reaction
ΔH = enthalpy of the reaction
From the above diagram,
Ea = Ea' + ΔH
Thus, Ea > ΔH
