`Cl_(2)(g)rarr2Cl(g)`, In this process value of `Delta H` will be -

Options

A. Positive
B. Negative
C. Zero
D. Nothing can be predicted

Answer

To determine the value of ΔH for the reaction \( \text{Cl}_2(g) \rightarrow 2\text{Cl}(g) \), we need to analyze the process of bond breaking and its relation to enthalpy change.

### Step-by-Step Solution:

1. **Identify the Reaction**: The reaction involves the dissociation of chlorine gas (\( \text{Cl}_2 \)) into two chlorine atoms (\( 2\text{Cl} \)).

2. **Understand Bond Breaking**: In the process of breaking the bond in \( \text{Cl}_2 \), energy is required to overcome the bond energy. This means that energy must be supplied to break the bond between the two chlorine atoms.

3. **Enthalpy Change (ΔH)**: The enthalpy change for a reaction can be calculated using the formula:
\[ \Delta H = \text{(Sum of enthalpy of products)} - \text{(Sum of enthalpy of reactants)} \]
In this case, the products are \( 2\text{Cl} \) and the reactant is \( \text{Cl}_2 \).

4. **Calculate the Enthalpy Change**:
- The enthalpy of the reactant \( \text{Cl}_2 \) will be a certain value (let's denote it as \( \Delta H_{\text{reactant}} \)).
- The enthalpy of the products \( 2\text{Cl} \) will require energy equal to the bond dissociation energy of \( \text{Cl}_2 \) (let's denote this as \( \Delta H_{\text{product}} \)).
- Since energy is absorbed to break the bond, the value of \( \Delta H \) will be positive.

5. **Conclusion**: Since the bond is broken and energy is absorbed, the overall change in enthalpy \( \Delta H \) for the reaction \( \text{Cl}_2(g) \rightarrow 2\text{Cl}(g) \) will be positive.

### Final Answer:
Thus, the value of \( \Delta H \) for the reaction \( \text{Cl}_2(g) \rightarrow 2\text{Cl}(g) \) is positive.