`CaCO_(3) hArr CaO + CO_(2)` reaction in a lime kiln goes to completion because

Options

A. CaO does not react with `CO_(2)` to give `CaCO_(3)`
B. Backward reaction is very slow
C. `CO_(2)` formed escapes out
D. All of these

Answer

To solve the question regarding why the reaction \( \text{CaCO}_3 \rightleftharpoons \text{CaO} + \text{CO}_2 \) in a lime kiln goes to completion, we can follow these steps:

### Step 1: Understand the Reaction
The reaction involves the thermal decomposition of calcium carbonate (\( \text{CaCO}_3 \)) into calcium oxide (\( \text{CaO} \)) and carbon dioxide (\( \text{CO}_2 \)). This is a common reaction that occurs in a lime kiln.

### Step 2: Identify the Conditions in a Lime Kiln
In a lime kiln, limestone (calcium carbonate) is heated to high temperatures. This environment is designed to facilitate the decomposition of limestone into lime (calcium oxide) and carbon dioxide gas.

### Step 3: Analyze the Formation of Products
As the reaction proceeds, \( \text{CaO} \) is formed as a solid, and \( \text{CO}_2 \) is produced as a gas. The gaseous \( \text{CO}_2 \) can escape from the kiln.

### Step 4: Consider the Concept of Equilibrium
In a reversible reaction, equilibrium is established when the rate of the forward reaction equals the rate of the backward reaction. However, in this case, the \( \text{CO}_2 \) gas escapes from the system.

### Step 5: Conclude Why the Reaction Goes to Completion
Since \( \text{CO}_2 \) is continuously removed from the reaction mixture as it is formed, the concentration of \( \text{CO}_2 \) does not build up. This prevents the backward reaction (where \( \text{CaO} \) and \( \text{CO}_2 \) would recombine to form \( \text{CaCO}_3 \)) from occurring significantly. Therefore, the reaction effectively goes to completion.

### Final Answer
The reaction \( \text{CaCO}_3 \rightleftharpoons \text{CaO} + \text{CO}_2 \) goes to completion because the \( \text{CO}_2 \) formed escapes out of the system, preventing the establishment of equilibrium.