Which of the following change will shift the reaction in forward direction?
`I_(2)(g) hArr 2I(g), DeltaH^(ɵ)=+150 kJ`

Options

A. Increase in total pressure
B. Increase in temperature
C. Increse in concentration of `I`
D. Decrease in concentration of `I_(2)`

Answer

To determine which change will shift the reaction \( I_2(g) \rightleftharpoons 2I(g) \) in the forward direction, we can apply Le Chatelier's principle. This principle states that if a system at equilibrium is subjected to a change in concentration, temperature, or pressure, the equilibrium will shift in a direction that counteracts the change.

### Step-by-Step Solution:

1. **Identify the Reaction Type**:
The reaction is given as \( I_2(g) \rightleftharpoons 2I(g) \) with a positive enthalpy change (\( \Delta H^\circ = +150 \, kJ \)). This indicates that the reaction is endothermic, meaning it absorbs heat.

**Hint**: Recognize whether the reaction is endothermic or exothermic by looking at the sign of \( \Delta H \).

2. **Analyze Changes in Concentration**:
- Increasing the concentration of \( I_2 \) (the reactant) will shift the equilibrium towards the products (forward direction).
- Conversely, increasing the concentration of \( I \) (the product) will shift the equilibrium towards the reactants (backward direction).

**Hint**: Changes in concentration of reactants or products affect the equilibrium position.

3. **Analyze Changes in Temperature**:
- Since the reaction is endothermic, increasing the temperature will shift the equilibrium towards the products to absorb the added heat (forward direction).
- Decreasing the temperature would favor the reactants (backward direction).

**Hint**: For endothermic reactions, increasing temperature favors the forward reaction.

4. **Analyze Changes in Pressure**:
- The reaction has 1 mole of gas on the reactant side (I2) and 2 moles of gas on the product side (2I). Increasing pressure will favor the side with fewer moles of gas, which is the reactants (backward direction).
- Therefore, decreasing pressure will favor the forward reaction.

**Hint**: The side with fewer gas moles is favored by increased pressure.

5. **Summarize the Conditions Favoring Forward Reaction**:
- Increase in concentration of \( I_2 \) (reactant).
- Increase in temperature.
- Decrease in pressure.

6. **Evaluate Given Options**:
- **Increase in total pressure**: This will shift the reaction backward.
- **Increase in temperature**: This will shift the reaction forward.
- **Increase in the concentration of \( I \)**: This will shift the reaction backward.
- **Decrease in the concentration of \( I_2 \)**: This will also shift the reaction backward.

**Conclusion**: The only change that will shift the reaction in the forward direction is **increase in temperature**.

### Final Answer:
**Increase in temperature** will shift the reaction in the forward direction.