Among the following for which reaction heat of reaction represents bond energy of HCl

Options

A. `HCl(g)rarr H^(+)(g)+Cl^(-1)(g)`
B. `HCl(g)rarr 1//2 H_(2)(g)+1//2Cl_(2)(g)`
C. `2HCl(g)rarr H_(2)(g)+Cl_(2)(g)`
D. `HCl(g)rarr H(g)+Cl(g)`

Answer

To determine which reaction's heat of reaction represents the bond energy of HCl, we need to analyze the options provided (though they are not listed here). The bond energy of HCl can be understood through its dissociation into its constituent atoms or molecules. Let's break down the steps:

### Step-by-Step Solution:

1. **Understanding Bond Energy**:
- Bond energy is the amount of energy required to break one mole of a bond in a gaseous substance. For HCl, we are interested in the bond energy of the H-Cl bond.

2. **Identifying the Reaction**:
- We need to find a reaction that involves the dissociation of HCl into its elements. The relevant reaction can be represented as:
\[ 2 \text{HCl(g)} \rightarrow \text{H}_2(g) + \text{Cl}_2(g) \]
- This reaction shows the decomposition of hydrogen chloride gas into hydrogen gas and chlorine gas.

3. **Calculating Heat of Reaction**:
- The heat of reaction (ΔH) for this process can be calculated using the bond energies of the products and reactants. The bond dissociation energies involved are:
- H-H bond energy (for H2)
- Cl-Cl bond energy (for Cl2)
- The heat of reaction can be expressed as:
\[ \Delta H = \text{Bond Energy of H-H} + \text{Bond Energy of Cl-Cl} - \text{Bond Energy of H-Cl} \]

4. **Using the Heat of Formation**:
- The heat of formation of HCl is known to be approximately -92 kJ/mol. This value indicates that when HCl is formed from its elements, energy is released, which is equivalent to the bond energy of HCl when it is broken.

5. **Conclusion**:
- The correct reaction for which the heat of reaction represents the bond energy of HCl is the one that involves the dissociation of HCl into its constituent elements, which is typically represented as:
\[ 2 \text{HCl(g)} \rightarrow \text{H}_2(g) + \text{Cl}_2(g) \]
- Thus, if option D corresponds to this reaction, it is the correct answer.

### Final Answer:
The reaction for which the heat of reaction represents the bond energy of HCl is:
\[ 2 \text{HCl(g)} \rightarrow \text{H}_2(g) + \text{Cl}_2(g) \]
Therefore, the correct option is **D**.