Consider the reaction
`CaCO_(3)(s) hArr CaO(s) +CO_(2)(g)`
in closed container at equilibrium. What would be the effect of addition of `CaCO_(3)` on the equilibrium concentration of `CO_(2)`?

Options

A. Increase
B. Decreases
C. Remains unaffected
D. Data is not sufficient to predict it

Answer

To solve the question regarding the effect of adding \( \text{CaCO}_3 \) on the equilibrium concentration of \( \text{CO}_2 \) in the reaction:

\[ \text{CaCO}_3(s) \rightleftharpoons \text{CaO}(s) + \text{CO}_2(g) \]

we will follow these steps:

### Step 1: Understand the Reaction
The reaction involves solid calcium carbonate decomposing into solid calcium oxide and gaseous carbon dioxide. The key point here is that \( \text{CaCO}_3 \) and \( \text{CaO} \) are solids, while \( \text{CO}_2 \) is a gas.

### Step 2: Identify the Equilibrium Expression
For this reaction, the equilibrium constant \( K_p \) is defined based on the partial pressures of the gaseous products. The equilibrium expression is:

\[ K_p = P_{\text{CO}_2} \]

where \( P_{\text{CO}_2} \) is the partial pressure of carbon dioxide.

### Step 3: Analyze the Effect of Adding \( \text{CaCO}_3 \)
When we add more \( \text{CaCO}_3 \) (a solid) to the system, we need to consider how this affects the equilibrium. Since the concentration (or activity) of solids does not change in a way that affects the equilibrium constant, the addition of more \( \text{CaCO}_3 \) does not change the partial pressure of \( \text{CO}_2 \).

### Step 4: Conclusion
Since the equilibrium constant \( K_p \) remains unchanged and the concentration of solids does not affect the equilibrium position, the concentration of \( \text{CO}_2 \) remains unaffected by the addition of \( \text{CaCO}_3 \).

Therefore, the final answer is:

**The equilibrium concentration of \( \text{CO}_2 \) remains unaffected.**

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