For an endothermic reaction, energy of activation is Ea and enthalpy of reaction is H (both of these in kJ/mol). Minimum value of Ea will be
- less than H
- equal to H
- more than H
- equal to zero
Answer
(3) more than H
Solution
For an endothermic reaction the products lie higher in energy than the reactants by H.
The activated complex (transition state) lies above the products, so
Ea = H + Ea' (where Ea' = activation energy of the backward reaction)
∵ Ea' > 0
∴ Ea > H; the minimum value of Ea is more than H (it can at best approach H).
Answer: (3)