In the dissociation of `CaCO_(3)` in a closed vessel, the forward reaction is favoured by

Options

A. adding some more` CaCO_(3)`
B. removing some CaO
C. increasing the pressure
D. removing `CO_(2)`

Answer

To solve the question regarding the dissociation of calcium carbonate (CaCO₃) in a closed vessel, we need to analyze the reaction and apply Le Chatelier's principle.

### Step-by-Step Solution:

1. **Identify the Reaction**:
The dissociation of calcium carbonate can be represented as:
\[ \text{CaCO}_3 (s) \rightleftharpoons \text{CaO} (s) + \text{CO}_2 (g) \]
Here, solid calcium carbonate dissociates into solid calcium oxide and gaseous carbon dioxide.

2. **Understand the System**:
In a closed vessel, the reaction reaches a state of equilibrium where the rate of the forward reaction (dissociation of CaCO₃) equals the rate of the reverse reaction (formation of CaCO₃ from CaO and CO₂).

3. **Apply Le Chatelier's Principle**:
Le Chatelier's principle states that if a system at equilibrium is subjected to a change in concentration, pressure, or temperature, the system will adjust to counteract that change and restore a new equilibrium.

4. **Analyze the Options**:
- **Adding more CaCO₃**: This would not favor the forward reaction since it would increase the concentration of the solid reactant, but solids do not affect the equilibrium position.
- **Removing some CaO**: This would not significantly affect the equilibrium since CaO is a solid and does not change the concentration of gases in the system.
- **Increasing the pressure**: This would favor the side with fewer moles of gas. In this case, since we have one mole of CO₂ gas produced, increasing the pressure would not favor the forward reaction.
- **Removing CO₂**: This would decrease the concentration of one of the products (CO₂), causing the equilibrium to shift to the right (forward direction) to produce more CO₂.

5. **Conclusion**:
Based on the analysis, the forward reaction (dissociation of CaCO₃) is favored by **removing CO₂** from the system. This is because it reduces the concentration of the product, prompting the equilibrium to shift towards the right to produce more CO₂.

### Final Answer:
The forward reaction is favored by **removing CO₂** from the equilibrium mixture.