For which of the following reaction `DeltaH_("reaction")^(@)` is not equal to `DeltaH_(f)^(@)` of product ?

Options

A. `2CO(g) + O_(2)(g) rarr 2CO_(2)(g)`
B. `N_(2)(g) + O_(3)(g) rarr N_(2)O_(3)(g)`
C. `CH_(4)(g) + 2Cl_(2)(g) rarr CH_(2)Cl_(2)(l) + 2HCl(g)`
D. `Xe(g) + 2F_(2)(g) rarr XeF_(4)(g)`

Explanation

To determine for which of the following reactions the standard enthalpy change of the reaction (ΔH₀_reaction) is not equal to the standard enthalpy of formation (ΔH_f₀) of the product, we need to analyze each reaction provided.

### Step-by-Step Solution:

1. **Understanding ΔH₀_reaction and ΔH_f₀**:
- ΔH₀_reaction refers to the enthalpy change during a reaction at standard conditions (1 atm pressure and 25°C).
- ΔH_f₀ is the enthalpy change when one mole of a compound is formed from its elements in their standard states.

2. **Analyzing Each Reaction**:
- **Reaction A**: Formation of CO₂ from carbon (graphite) and O₂.
- The standard enthalpy of formation of CO₂ is defined as the enthalpy change when 1 mole of CO₂ is formed from its elements (C in graphite form and O₂ gas). Thus, ΔH₀_reaction = ΔH_f₀ for this reaction.

- **Reaction B**: Formation of O₃ from O₂.
- O₃ (ozone) is not formed from its standard elemental form (O₂ is the standard state for oxygen). Therefore, ΔH₀_reaction ≠ ΔH_f₀ for this reaction.

- **Reaction C**: Formation of CH₂Cl₂ and HCl from carbon and chlorine.
- This reaction involves the formation of two products (CH₂Cl₂ and HCl) from their elements. The enthalpy of formation is defined only for the formation of one mole of a compound from its elements in their standard states. Therefore, ΔH₀_reaction ≠ ΔH_f₀ for this reaction.

- **Reaction D**: Formation of XeF₄ from xenon and fluorine.
- This reaction involves the formation of XeF₄ from its elements (Xe gas and F₂ gas), which are in their standard states. Thus, ΔH₀_reaction = ΔH_f₀ for this reaction.

3. **Conclusion**:
- The reactions for which ΔH₀_reaction is not equal to ΔH_f₀ of the product are **B (formation of O₃)** and **C (formation of CH₂Cl₂ and HCl)**.

### Final Answer:
The reactions for which ΔH₀_reaction is not equal to ΔH_f₀ of the product are **B and C**.