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 `CaCO3` on the equilibrium concentration of `CO2` 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 the decomposition of solid calcium carbonate (`CaCO3`) into solid calcium oxide (`CaO`) and gaseous carbon dioxide (`CO2`).

### Step 2: Identify the State of Reactants and Products
In this reaction:
- `CaCO3` and `CaO` are solids.
- `CO2` is a gas.

### Step 3: Write the Expression for the Equilibrium Constant
The equilibrium constant expression for this reaction can be written as:

\[ K_c = \frac{[\text{CO}_2]}{1} \]

Since solids do not appear in the equilibrium expression, we only consider the concentration (or partial pressure) of the gaseous product `CO2`.

### Step 4: Apply Le Chatelier's Principle
According to Le Chatelier's principle, if a system at equilibrium is disturbed, the system will shift in a direction to counteract the disturbance. However, the addition of a solid (in this case, `CaCO3`) does not change the concentration of the gaseous product because:
- The concentration of solids is constant and does not affect the equilibrium position.

### Step 5: Conclusion
Therefore, the addition of `CaCO3` will not affect the equilibrium concentration of `CO2`. The system remains unaffected by changes in the amounts of solids present.

### Final Answer
The equilibrium concentration of `CO2` remains unaffected by the addition of `CaCO3`.

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