The enthalpy change of a reaction does not depend on

Options

A. State of reactants and products
B. Nature of reactants and products
C. Different intermediate reactions
D. Initial and final enthalpy change of reaction

Answer

To solve the question regarding the factors that do not affect the enthalpy change of a reaction, we can analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding Enthalpy Change**:
- Enthalpy change (ΔH) for a reaction is defined as the difference between the enthalpy of the products and the enthalpy of the reactants.
- Mathematically, it can be expressed as:
\[ \Delta H = \sum \Delta H_{\text{products}} - \sum \Delta H_{\text{reactants}} \]

2. **Analyzing the Options**:
- **Option A: State of Reactants and Products**:
- The enthalpy change does depend on the physical state (solid, liquid, gas) of the reactants and products because different states have different enthalpy values. Therefore, this option is incorrect.

- **Option B: Nature of Reactants and Products**:
- The nature (atomic, molecular, ionic) of the reactants and products also affects the enthalpy change. Different substances have different enthalpy values based on their chemical nature. Thus, this option is also incorrect.

- **Option C: Different Intermediate Reactions**:
- The enthalpy change of a reaction is independent of the pathway taken to reach the products from the reactants. This means that the presence of intermediates does not affect the overall enthalpy change. Therefore, this option is correct.

- **Option D: Initial and Final Enthalpy Changes**:
- The enthalpy change is calculated based on the initial and final states of the reactants and products. Thus, this option is incorrect.

3. **Conclusion**:
- The correct answer is **Option C: Different Intermediate Reactions**. The enthalpy change does not depend on the different intermediate reactions that may occur during the transformation from reactants to products.