For an endothermic reaction energy of activation is `E_(a)` and enthlpy of reaction is `Delta H` (both in `kJ "mol"^(-1)`). Minimum value of `E_(a)` will be

Options

A. Less than `DeltaH`
B. Equal to `Delta H`
C. More than `Delta H`
D. equal to zero

Explanation

To determine the minimum value of the activation energy \(E_a\) for an endothermic reaction, we need to understand the relationship between the activation energy, the enthalpy change of the reaction (\(\Delta H\)), and the energy profile of the reaction.

### Step-by-Step Solution:

1. **Understanding Endothermic Reactions**:
- In an endothermic reaction, the products have higher energy than the reactants because energy is absorbed during the reaction. This means that \(\Delta H\) (enthalpy change) is positive.

2. **Energy Profile Diagram**:
- Draw an energy profile diagram. The x-axis represents the progress of the reaction, while the y-axis represents the energy.
- The energy level of the reactants is lower than that of the products.

3. **Activation Energy (\(E_a\))**:
- The activation energy is the energy barrier that must be overcome for the reactants to be converted into products. In the diagram, this is represented as the energy difference between the reactants and the peak of the energy barrier (transition state).

4. **Relationship Between \(E_a\) and \(\Delta H\)**:
- For an endothermic reaction, the relationship can be expressed as:
\[ E_a = \Delta H + E_{a, \text{backward}} \]
- Here, \(E_{a, \text{backward}}\) is the activation energy for the reverse reaction (from products back to reactants).

5. **Minimum Value of \(E_a\)**:
- Since \(E_{a, \text{backward}}\) is always a positive value (as it requires energy to convert products back to reactants), the minimum value of \(E_a\) must be greater than \(\Delta H\).
- Therefore, we conclude:
\[ E_a > \Delta H \]

6. **Conclusion**:
- The minimum value of the activation energy \(E_a\) for an endothermic reaction is greater than the enthalpy change \(\Delta H\).

### Final Answer:
The minimum value of \(E_a\) is greater than \(\Delta H\).