For the reaction, `PCl_(3)(g)+Cl_(2)(g) hArr PCl_(5)(g)`, the position of equilibrium can be shifted to the right by:

Options

A. Doubling the volume
B. Increasing the temperature
C. Addition of equimolar quantities of `PCl_(3)` and `PCl_(5)`
D. Addition of `Cl_(2)` at constant volume

Answer

To determine how the position of equilibrium for the reaction \( PCl_3(g) + Cl_2(g) \rightleftharpoons PCl_5(g) \) can be shifted to the right, we can analyze the factors that affect equilibrium according to Le Chatelier's principle.

### Step-by-step Solution:

1. **Understanding the Reaction**:
The reaction involves the conversion of phosphorus trichloride (\( PCl_3 \)) and chlorine gas (\( Cl_2 \)) into phosphorus pentachloride (\( PCl_5 \)). The equilibrium can be affected by changes in concentration, pressure, and temperature.

2. **Applying Le Chatelier's Principle**:
According to Le Chatelier's principle, if a system at equilibrium is disturbed, the system will adjust itself to counteract the disturbance and restore a new equilibrium. This means that if we increase the concentration of the reactants, the equilibrium will shift to the right to produce more products.

3. **Evaluating the Options**:
- **Doubling the Volume**: This would decrease the pressure and could shift the equilibrium to the side with more moles of gas, which is not favorable for this reaction.
- **Increasing the Temperature**: This reaction is exothermic (producing heat), so increasing the temperature would shift the equilibrium to the left (favoring the reactants).
- **Adding Equimolar Quantities of \( PCl_3 \) and \( PCl_5 \)**: This does not change the concentration of \( Cl_2 \) and could potentially shift the equilibrium to the left or have no significant effect.
- **Adding \( Cl_2 \) at Constant Volume**: This increases the concentration of one of the reactants (\( Cl_2 \)), which according to Le Chatelier's principle, will shift the equilibrium to the right to produce more \( PCl_5 \).

4. **Conclusion**:
The correct way to shift the equilibrium to the right is by adding \( Cl_2 \) at constant volume.

### Final Answer:
The position of equilibrium can be shifted to the right by the addition of \( Cl_2 \) at constant volume.

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