Concept:In an endothermic reaction, the products have a higher potential energy than the reactants. Therefore, the energy barrier from the reactant side is larger than from the product side.
Formula:$$ \Delta H = E_{a(\text{forward})} - E_{a(\text{backward})} > 0 $$
Solution:- Because the reaction absorbs heat, the enthalpy change (\( \Delta H \)) is positive.
- This means the activation energy for the forward reaction (\( E_{a(\text{forward})} \)) must be strictly greater than the activation energy for the reverse/backward reaction (\( E_{a(\text{backward})} \)).
- Consequently, the backward activation energy is less than the forward activation energy.
Why other options are incorrect:If forward activation energy is less, the reaction is exothermic. They are only the same if \( \Delta H = 0 \) (a thermoneutral reaction).
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